法律教育网

法律英语

2019瑞达法考客观题学习包

考试内容 报名条件 报名时间 报名方法

成绩查询 考试时间 分 数 线 授予资格

您的位置:法律教育网 > 法律英语 > 法律术语 > 正文

【证据的本质】中英互译

2012-01-02 09:41  来源:   纠错

  the Nature of Evidence

  Evidence is any statement or material object from which reasonable conclusions can be drawn. It is a broad category embracing anything perceptible to the five senses including documents, exhibits, facts agreed to by both sides, and the testimony of witnesses. Evidence in a criminal trial concerns the intent, motive, means, and opportunity to commit a crime.

  In general, evidence is divided into two categories: circumstantial and physical. Circumstantial evidence consists of information gleaned from witnesses and documents that point to an individual as the perpetrator of a crime. Physical evidence consists of actual objects ?bodies, weapons, body fluid stains, fingerprints, hairs, fibers, etc. ?that are associated with the crime and may be linked to the perpetrator.

  It is the work of forensic scientists to examine the physical evidence, and using the methods of science, to reconstruct the events that constituted the crime. The prosecutor must then combine this data with statements of witnesses and evidence from documents such as correspondence, telephone records and credit card receipts to develop an overall theory of the case which can be presented in court.

  Scientific evidence is an increasingly important part of both civil and criminal trials. Forensic science is a growth industry. New technologies for analyzing physical evidence are growing rapidly and private companies are becoming an increasingly important resource for the legal system. The testimony of experts is the primary means of introducing scientific evidence. Because these experts are imparting information “beyond the ken” of the layperson, they must present information that goes beyond first hand observation, opinions and hearsay not permitted under ordinary rules of evidence. Lay witnesses are constrained to testify only about matters they have directly observed. Expert witnesses are allowed to draw inferences from facts which the judge or jury is not competent to draw. They may also rely on seminars, publications, records and conversations with other experts that are part of their normal course of business.

  Discovery

  Despite fictional presentations to the contrary (Perry Mason is a prime example), there are very few surprises in actual trials. This is because of the process called discovery, whereby opposing attorneys are permitted to learn the facts and expert opinions upon which the other side is basing its case prior to the actual trial. In addition, each side is required to provide the other side with a list of its witnesses before the start of trial.

  Providing discovery materials in criminal cases is binding only upon the prosecution in all but a few states and Canada. Access to materials through the discovery process is the main avenue the defense has for learning what evidence will be presented against the accused at trial. This allows the defense to re-examine the evidence and develop alternative hypotheses to the prosecutor's case.

  In California, the defense's access to scientific evidence is defined in the Griffin decision which provides that the defense can have the evidence only after the prosecution has completed their testing. Also, under both Griffin and a U.S. Supreme Court decision in Arizona v. Youngblood, the prosecution may consume the evidence in the testing process, as long as they act in good faith.

  Beginning in 1989, furious battles erupted over discovery efforts in the DNA war. Gen-erally the defense has been able to examine autoradiographs from the case in question, laboratory reports, and the lab notes that support them in addition to the lab procedure manuals and proficiency testing results. Requests for additional materials such as other autoradiographs, validation studies, population data bases, and raw data face harsher scrutiny and often were not honored. Early DNA cases were marked by long and costly litigation over discovery. The defense claims that the prosecution and the labs they employ “stonewall' discovery requests. The lab resist discovery, maintaining that the requested materials are privileged, constitute trade secrets, are legally irrelevant.

  Forensic labs also claim that the defense regularly makes overly burdensome and duplicitous requests for reams of material. If they were required to comply, lab personnel would be doing little else than identifying and duplicating discovery materials. DNA discovery battles are still being strenuously fought. Indeed, O.J. Simpson's chief lawyer, Robert Shapiro, has labeled Cellmark a “discovery outlaw.” However most commentators would agree that many of the issues surrounding discovery already have been litigated or settled in other ways.

  Scientific Evidence Admissibility Standards

  The key element in whether scientific evidence is admissible is whether it is trustworthy. To be considered trustworthy, it must demonstrate accuracy (validity) and consistency (reliability)。 Admissibility is determined by the Frye rule, which stresses “general acceptance” or by the Federal Rules of Evidence (followed by some state courts) which stress helpfulness, reliability, and relevance.

  In all of the trials to date in which DNA evidence has been involved, courts have ruled it as evidence or, on appeal, have remanded the case to the trial court in 22 reported cases and have limited its admissibility in 16 cases, generally because of statistical questions.

  The Frye Standard

  In the 1923 decision United States v. Frye, a District of Columbia circuit court ruled against the admissibility of lie detector evidence in a murder case because the technology had not been accepted in the relevant scientific community. Since then, most state courts have followed this general standard on whether or not to allow novel scientific evidence. The so-called Frye hearing gives the prosecution and defense the opportunity to attack adverse scientific evidence and try to keep it out of the trial. The key paragraph in this decision reads:

  Just when a scientific principle or discovery crosses the line between experimental and demonstratable stages is difficult to define. Somewhere in the twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. Determining “general acceptance” according to the Frye standard is a two-step procedure: (1) identifying the particular field(s) into which the scientific principle or discovery falls and the relevant scientific community; and (2) determining whether that community accepts the technology, principle, or discovery. Both the underlying theory and the procedures used to produce results must be generally accepted by scientists in the relevant fields.

  To these two criteria has been added a third in some jurisdictions. In California, the additional standard evolved from the 1976 decision in People v. Kelly which held that “the proponent of the evidence must demonstrate that correct scientific procedures were done in the particular case.” This third “prong” also was accepted by the court in the 1989 landmark New York v. Castro, the first case in history of where DNA evidence was excluded. A distinction lost on some courts is that the Kelly rule only requires that correct procedures be used, not that the court must determine that these procedures were performed correctly.

  Legal evidence rules generally hold that how well work is performed should not be the subject of an admissibility hearing because the quality of testing in a particular case goes to the weight of the evidence and not its admissibility. It is up to the trier of fact, the judge or the jury, to determine how much weight or consideration to give that evidence. In practice, the legal distinction between the admissibility of scientific testing and the weight that should be given that testing has become increasingly blurred in DNA evidenciary hearings.

  It should be noted that, at least in California, the Frye rule does not require absolute “unanimity of views within the scientific community,” which, according to the California Court of Appeals, would “demand the impossible.” In People v. Guerra (restated in the Reilly case), the court ruled that, “the test is met if the use of the technique is supported by a clear majority of the members of that community.” Nevertheless, some courts have interpreted “general acceptance” to mean the absence of controversy, an unrealistic standard in almost any scientific or technical area.

  One result of this interpretation is that Frye hearings often last longer than many trials. The mother of all Frye hearings took place in San Diego in 1987. At issue was the methodology of pre-DNA blood typing. A personal vendetta between two experts, known as the “starch wars,” exacerbated the controversy which dragged on for a full year. While courts and attorneys are often reluctant to reveal the costs of proceedings, Frye hearings are expensive.

  In King County (Seattle), Washington the situation may be the worst in the country. There have been over a dozen pre-trial DNA evidentiary hearings in this jurisdiction, each requiring two to six weeks of courtroom time. Most have concerned identical technologies and laboratories. In total, these hearings are estimated to have cost the local government over $1,000,000, not counting the time that personnel such as bailiffs and guards, attorneys, experts and others have lost to more productive tasks. This might be a reasonable price to pay if the controversy had been finally settled, but at this point there is no end in sight. All costs are paid by the state in more than 90% of these cases because the defendant is indigent.

  The Frye rule has been criticized for its overly conservative approach and its vulnerability to manipulation by those seeking to exclude novel scientific evidence. After the Federal Rules of Evidence were enacted, a number of jurisdictions abandoned Frye.

  The Federal Standard

  The Federal Rules of Evidence currently in force were promulgated by the Supreme Court and enacted by Congress in 1975. While they are applicable directly only to proceedings in federal courts, they serve as the model for evidence codes in 32 states. Despite this state recognition of federal standards, the majority of states profess to follow the Frye rule, creating evidenciary ambiguity that may not be resolved until appellate courts or legislatures address the issue.

  While not explicitly repudiating the Frye rule, the Federal Rules adopt a more permissive approach. They liken the standard for scientific evidence to that for other evidence, i.e. whether the probativeness, materiality, and reliability of the evidence outweighs its tendency to mislead, prejudice, and confuse the jury. The judge has more discretion under the Federal Rules.

  Rule 702, which concerns admissibility, states:

  if scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise. Rule 703 requires that the facts or data presented be “of a type reasonably relied on by experts in the particular field.” Rule 403 excludes evidence that would cause undue prejudice or confusion. Proponents of the Federal Rules approach to admissibility believe that taken together, these rules address all the concerns embodied in the Frye rule.

  Daubert v. Merrell Dow

  Critics of the Federal Rules fear that the courts may be opening themselves to “junk science” by relaxing Frye, but a landmark case heard by the Supreme Court in 1993 rejected that claim. In Daubert v. Merrell Dow Pharmaceutical, Inc., the court unanimously held that the Frye rule was incompatible with and had been superseded by the adoption of the Federal Rules. It found that “vigorous cross-examination, presentation of contrary evidence, and careful [jury] instruction are the traditional and appropriate means of attacking shaky but admissible evidence.” Trial courts also could still render summary judgments and directed verdicts where there was an insufficient showing of reliability.

  The effect of Daubert on states where rules mirror federal standards has yet to be felt. However, it is reasonable to assume that expert testimony on DNA will be admissible after a threshold finding that it is relevant and reliable. Defendants in these jurisdictions will have a harder time suppressing DNA evidence, although stiff challenges to its admissibility will undoubtedly continue, at least for the near future. Daubert will have little or no effect on states where Frye still prevails. Some of the states even have supreme court decisions affirming Frye. The most recent state to affirm Frye is California in the Leahy case, decided in October 1994. In these states, new high court decisions or legislation are the only means to change admissibility standards.

  Legislated Admissibility

  By the Fall of 1994, eleven states had statutes mandating the admissibility of DNA evidence. Maryland became the first state to do so followed by Minnesota, Louisiana, and Nevada, all in 1989. Most of the legislation contains language that DNA testing is acceptable “without antecedent expert testimony” that it is “a trustworthy and reliable method.” Arguably, these laws do not cover DNA analysis methods introduced after their passage, and the defense may still challenge laboratory performance and the statistical interpretation of results. As a more sophisticated defense bar mounts increasing numbers of expensive challenges to DNA evidence, it is likely that additional state legislatures will address this issue.

  Expert Witnesses

  While many expert witnesses represent the best in their profession, the proliferation of expert witnesses, often considered to be “hired guns” employed to shoot holes in the other side's testimony, is a remarkable development in the criminal justice system. There is hardly any kind of case not affected by these duelling experts, but psychological, medical, and DNA testimony seems to bring out the worst of them. It is difficult not to conclude that some of these individuals are willing to stretch or ignore the facts, distort the science, and become “liars for hire.” Many of these witnesses derive a substantial amount or even the bulk of their income from testifying, which should be considered in determining their credibility and weighing their testimony. One California judge bemoaned the use of such witnesses by candidly calling them the beneficiaries of “a welfare system for academics.” A recent article on the ethics and responsibility of expert witnesses suggests the following criteria for qualification:

  Undergraduate and graduate degrees in the relevant field of expertise;Specialized training in the subject area as it relates to forensic science;Some training in forensics;Professional licenses or certifications required by professional groups in the expert's discipline;Evidence of experimentation, teaching, and publication within the specialty area; and Prior disciplinary evidence directly relevant to the issues being considered.

  Other elements that help to determine an expert's qualifications include: post-graduate training, publication in peer-reviewed scientific journals, the development of accepted tests and procedures, membership or leadership in appropriate scientific societies, and, only lastly, experience as an expert witness.

  Ten years ago the Califonia case People v. Brown added criteria that has proven difficult to apply, ie., that the witness “must also be 錳mpartial,' that is, not so personally invested in establishing the acceptance of a technique that he might not be objective about disagreements within the relevant scientific community.” Neither should a witness be so invested in denigrating a technique that he exaggerates the disagreement within the scientific community. Probably the best way of gaining the testimony of impartial witnesses is for courts, rather than litigants, to appoint and pay for expert witnesses. Such is the practice in many other countries. While it is unusual in the U.S, this procedure is within the power of state and federal courts. A notable example in a case involving DNA was United States v. Yee, where the magistrate called Eric Lander, a mathematician-turned-geneticist, as an expert witness to supplement the seventeen expert witnesses called by the prosecution and defense. It is reported that Judge Ito may call his own expert witnesses during the Simpson case Kelly-Frye hearing.

  Defense Strategy

  Defense witnesses mount various objections to DNA evidence. They no longer try to discredit the technology itself. Years ago, DNA typing achieved such wide acceptance and proven reliability that opponents now concentrate on two principal points of attack: (1) the quality and methodology of the laboratory work, including the lab's error rate, and (2) the statistical interpretation of data. The focus of the attacks on admissibility have changed over time. As one objection was knocked down, DNA opponents came up with another. The quality and relevancy of the arguments and of the experts is decreasing, having gone from population geneticists to bio-statisticians to statisticians from completely unrelated fields. What follows is a summary of the most frequently heard complaints about DNA typing and the responses to them that might be expected from forensic scientists. More technical objections, such as bandshifting and laboratory quality assurance, are addressed in Chapter Three.

  Conflict of Interest

  Prosecution and defense expert witnesses in DNA cases are arguably the most contentious and disparaging in the business. Several judges have remarked that Frye hearings over DNA can be extremely vicious. Among the charges and countercharges hurled back and forth is that the opposing witnesses should be disqualified from testifying because of a conflict of interest. To a certain extent, both sides are correct. The prosecution believes that defense witnesses in DNA hearings often have a vested interest in making sure that the subject stays controversial so that they can continue the lucrative practice of testifying. The defense often believes that a practicing forensic scientist has a built-in bias or predisposition toward the prosecution's side because of the close working relationship between crime labs and law enforcement. Indeed, criminalists often are police employees.

  If the forensic scientists are leaders in their field, they may be subject to a further conflict of interest. If they have developed or invented techniques or tools, they may have a proprietary interest in advancing DNA testing. They may have financial holdings in DNA labs or may have received grant funding from public or private agencies. Certainly, a jury is entitled to know about all of these connections which should be fully disclosed. At the same time, courts acknowledge that, “simply because learned experts earn a living with their expertise should not prohibit the admissibility of their opinions,” as the court ruled in a recent New Jersey case.

  Integrity of Specimen

  Opposing expert witnesses try to raise doubts about the way DNA evidence was gathered and tested claiming that contamination may have occurred. The usual argument is that the underlying procedures for forensic DNA testing were developed in laboratories where pure and known samples were used and retesting always was an option. While this is true, the argument doesn't mention the usual results of contamination, the ease with which it can be detected, and the safeguards that are in place in most forensic DNA labs.

  In almost all cases, the results of using a specimen sufficiently contaminated to alter test results simply would be ruled inconclusive. One way a specimen might be contaminated is by genetic material from the technician performing the analysis or from the person gathering the evidence. Again, this could not possibly harm the accused as an exclusion would be the result of such mishandling. Finally, there is the possibility that some of the DNA drawn from the suspect could be accidentally mixed with DNA retrieved from the crime scene. Such an accident would yield false results, especially if PCR amplification is used. To avoid this possibility, crime labs that perform PCR do it in isolation and under stringent conditions that minimize the risk of contamination.

  DNA analysis is undeniably better than other tests in analyzing mixed specimens and overcoming a variety of contaminants. Because of its structure and relative stability, DNA can be tested even after mixture with acids, bases, gasoline, oil, or bleach.

  Error Rate

  The newest objection, which is at the heart of the Simpson defense team's argument to exclude DNA evidence, is the testing lab's error rate. In a field as complicated as forensic science there are many sources of error, most of which will lead to an inconclusive or no result. A false positive or negative error rate is impossible to measure because these are such rare events. These are the types of errors caused by human error or fraud. It should be noted that most of these types of mix-ups or failures in the chain of custody would lead to a false negative result which would be work in the accused's favor. These also are more likely to occur before the evidence is received by the laboratory. There is no rate of these kinds of errors that is acceptable. Fortunately, an error resulting in a miscarriage of justice has yet to be demonstrated in forensic DNA casework, although it is perhaps inevitable that it will occur someday.

  Errors intrinsic to the testing systems, such as the inability to precisely measure DNA restriction fragment lengths, are well compensated for by interpretation guidelines which take these kinds of errors into account. The series of quality control steps built into the process also provide an excellent assurance of the quality of individual and laboratory performance. In most cases these steps should lead to corrective action long before a catastrophic error has occurred.

  Minimizing laboratory errors requires a quality control program such as the ones which already are in place on a voluntary basis in the forensic laboratories. Almost all forensic DNA laboratories participate in programs which include proficiency testing and confirm that a minimum level of performance has been achieved. External proficiency testing also provides an ongoing comparison of inter-laboratory measurement error. These programs, led by the American Society of Crime Laboratory Directors Laboratory Accreditation Board are rapidly gaining momentum.

  In the forensic field, the final arbiters of quality are the courts where experts under examination and cross-examination submit their results to the scrutiny of the opposing experts and the judge and jury. This added level of scrutiny is necessary to ensure quality forensic work and includes review of casework, retesting, and observation of particular tests by opposing experts. Both sides need to have equal access to forensic expertise in the interests of fairness and justice.

  Population Genetics Estimates

  The most contentious debate in forensic DNA involves the use of statistics to estimate the rarity of a given DNA profile. This is to be expected because the extraordinary rarity of these profiles is what gives them their conclusiveness as evidence. The rarities of the genetic profiles depend on the number of genes examined (usually four or five, often more)。 The frequencies of the results of each gene are multiplied to reach a combined profile frequency or the final estimate which is presented to the court.

  Critics contend that among certain ethnic sub-groups, there may be arrangements of gene frequencies that differ markedly from those found in the general population. They maintain that the population base used to give frequency statistics must be drawn from the suspect's particular gene pool, i.e., if a suspect is half Vietnamese and half French, the population database used to compute the probability ra

  证据的本质

  证据是从中可以推理出合理结论的任何陈述或者具体的物质。证据是一个很广泛的类别,可以包括任何可被五官感觉到的东西,具体包括书证、物证、双方同意的事实、证人证词等。刑事审判中的证据关系到犯罪的目的、动机、方法和机会等。

  一般来讲,证据被划分为两种,间接证据和实物证据。间接证据包括通过证人收集的信息以及指向某一个人为罪犯的书证。实物证据包括与犯罪有关或者与罪犯相联系的真实的物质,如尸体、武器、人体的液体斑点、指纹、毛发和纤维等。

  法医科学家的工作就是要检验实物证据,使用科学方法重建构成犯罪的事件。然后,控方必须将这些数据与证人证言、书证如信件、电话录音、信用卡收据等结合起来,以便能够在法庭演示整个案件过程。

  科学证据在民事和刑事审判中都占据着日益重要的地位。法医学是一个发展中的产业。分析实物证据的新技术正在迅速发展,私人公司正在成为司法系统日益重要的资源。专家证据是引入科学证据的最初方法。因为这些专家要向外行人讲授“外行人知识领域之外”的知识,他们就必须提出根据一般证据规则所不允许的直接观察资料、观点和传闻之外的知识。外行证人被限制在仅就他们直接观察到的事物作证。专家证人则被允许根据事实进行法官或者陪审团不能作出的推理。他们还可以根据他们的日常工作如讨论会、出版物、记录或者与其他专家的会谈等作出推理。

  发现程序

  尽管可以进行相反的假定推理(Perry Mason是主要的例子),在实际的审判中几乎不会出现任何惊人的发现。这是因为称之为“发现”的程序,根据这个程序,在实际的审判前,对方律师被允许获知另一方掌握的案件事实和专家意见。除此之外,在审判开始之前,每一方都必须提供给另一方一份证人名单。

  在刑事案件中提供发现材料是有限的,仅就指控事项提供材料,除了美国几个州和加拿大以外,其他地方一般都是如此。通过发现程序获取资料是辩方获得有关在法庭上控方将会呈现对被告不利的证据的信息的主要途径。这一程序保证了辩方对证据的再询问,以及研究对控方案件的替代性的假定。

  在加利福尼亚州,辩方有权使用科学证据是在格里芬案的判决中详细说明的,这个判决中说,辩方只有在控方完成鉴定后才能使用科学证据。同样,根据格里芬案以及美国最高法院在Arizona v. Youngblood案中的判决,控方可以毁灭证据,只要他们秉承善意。

  1989年初,就DNA之战中的发现程序爆发了一场激战。通常,除了实验室程序手册和熟练鉴定结果之外,辩方一直都能调查所涉案件的自动射线照相、实验室报告以及实验室记录等来支持他们。辩方要求额外的资料如其他自动射线照相、确认研究、人口资料数据和原始数据等则面临着苛刻的详细审查,并经常被拒绝。早期的DNA案件在发现程序上都是耗时耗力的,并因此而闻名。辩方主张控方和他们雇用的实验室都妨碍了辩方的发现请求。实验室反对辩方发现,并坚持主张说,辩方请求发现的资料是受到特权保护的,构成商业秘密,在法律上也是不相关的。

  法医实验室还主张,辩方定期要求他们提供极度繁重的、有意欺骗的大量材料,他们难以负担。如果他们必须要满足辩方要求的话,实验室的工作人员就无法从事其他的工作,只能从事鉴定和复制发现材料的工作了。DNA发现程序之战仍旧继续进行着。实际上,O.J.辛普森案件的主要律师,Robert Shapiro就赋予Cellmark以“发现逃犯”的称号。然而,大多数评论人士同意围绕着发现程序的许多问题已经通过诉讼或者其他途径解决了。

  科学证据的采纳标准

  在是否采纳科学证据的问题上的关键因素是科学证据是否是值得信赖的。要被认为是值得信赖的,它必须具有精确性(有效性)和连贯性(可靠性)。是否采纳可以根据Frye规则来判定的,这个规则强调“普遍接受”;或者根据联邦证据规则(许多州法院采纳此规则),这个规则强调有用性、可靠性和关联性。

  至今,在涉及DNA证据的所有审判中,法院裁决作为证据使用或者经上诉退回原法院审理的有22个案件,因此法院实际上采纳DNA证据的案件为16个,这主要是根据统计学统计出来的。

  Frye标准

  1923年,在United States v. Frye一案中,哥伦比亚地区巡回法院裁决否定了测谎器证据在谋杀案中的使用,因为该项技术还没有在相关的科学界得到接受。其后,大多数州法院就是否允许采纳新的科学证据方面都遵循了这一标准。所谓的Frye听证会为控方和辩方提供了攻击对己不利的科学证据的机会,并试图将之控制在庭审之外。该判决的关键段落写道:

  正当一个科学原理或者发现跨越了试验和论证阶段之间的界限时,它就很难定义了。在边缘地区,这个原理的证据力必须得到验证。当法院认可由公认的科学原理或发现中推论出来的专家证据时,推论的来源必须是经充分确定、并在其所属专门领域获得广泛接受的。

  根据Frye标准判定“普遍接受”是一个两步骤的程序:(1)确定科学原理或发现所属以及相关的科学界的专门领域;(2)判定是否该科学界已经接受该技术、原理或发现。基本的理论和用于产生结果的程序都必须得到相关领域科学家的普遍接受。

  在某些地区,还有第三条标准。在加利福尼亚州,第三条标准来源于1976年People v. Kelly一案中的判决,判决认为“证据的提出者必须证明在特定案件中采取了正确的科学程序。”这第三条标准在1989年法院对New York v. Castro这一划时代案件的判决中再次得到接受,这个案件是历史上排除DNA证据的第一个案件。后来的许多法院在适用这一标准时出现了差别,Kelly案件中的标准仅要求使用正确的程序,并没有要求法院判定这些程序是否被正确的执行。

  法定证据规则一般认为,程序如何更好的进行不应该是证据可采性听证会的主题,因为特定案件中鉴定质量影响的是证据的重要性而不是它的可采性。应该由审问者、法官或者陪审团来决定应该给予证据多大的重要性。实际上,在DNA证据听证会上,科学鉴定的可采性和重要性的法律差别已经变得越来越模糊了。

  应该注意的是,至少在加利福尼亚州,Frye规则也不需要“科学界内部观点的完全一致”,根据加利福尼亚上诉法院的观点,这种要求是“不可能的”。在People v. Guerra一案中(在Reilly案中重申),法院裁决道,“如果一项技术的使用被所属领域的多数成员接受就满足了鉴定的要求。”然而,一些法院将“普遍接受”解释为没有争议,这在几乎任何科学或技术领域都是不现实的标准。

  这种解释的一个结果是Frye听证会经常比许多庭审时间还要长。1987年,所有参与Frye听证会的人士在圣地亚哥召开会议,争议的问题是DNA鉴定之前血液类型的方法论问题。两位专家之间的个人恩怨,称为“淀粉之战”,加剧了这场争论,而后又延伸了一年。虽然法院和律师经常不愿披露诉讼成本,Frye听证会也是非常昂贵的。

  华盛顿的King县(西雅图)的情况可能是这个国家中最糟糕的。在这个区域内有超过12个审前DNA听证会,每个都需要2-6星期的审判时间。大多数案件都涉及同样的技术和实验室。总体上,据估计这些听证会要花费地方政府1百万多美元,还不包括下列人员如法警、狱警、律师、专家以及其他人失去的从事其他更加有价值的工作的时间。如果争议最终得以解决,这可能还是一个合理的价格,但是在目前这一点上,还无法确知争议的结束。90%的案件成本是由州来支付的,因为被告都比较穷困。

  因其方法上的过度保守和操作上的弱点,Frye规则一直受到那些寻求排除新奇科学证据的人士的批评。联邦证据规则颁布之后,许多地区都摒弃了Frye规则。

  联邦证据规则

  目前生效的联邦证据规则是在1975年由国会制定、最高法院颁布的。虽然它们仅直接适用于联邦法院的诉讼,但是它们在32个州内都作为证据法的范本。尽管各州对联邦标准的认可,多数州表示要遵循Frye规则,这就造成了证据上的不确定,除非上诉法院或者立法机关解决这个问题,否则这个问题无法得到解决。

  联邦证据规则虽然没有明确批判Frye规则,但是它们采纳了一种更加宽容的方法。它们将科学证据标准与其他标准相比较,如是否证据的检验性、实质性和可靠性会在价值上超过它使陪审团误导、形成偏见和混淆的倾向。根据联邦证据规则,法官有更大的自由裁量权。

  涉及到证据可采性的规则702规定:

  如果科学、技术、或者其他专门知识能够帮助事实的审问者了解证据或者判定争议中的事实,那么满足作为专家要求的知识、技能、经验、训练或者教育的证人就可以专家意见或者其他形式作证。

  规则703要求,提出的事实或者数据应该属于“某一专门领域专家合理信赖的种类”。规则403排除了会引起不适当的偏见或混淆的证据。联邦证据规则可采性方法的支持者相信,这些规则能够包含所有Frye规则中包含的事项。

  Daubert v. Merrell Dow

  联邦证据规则的批评者担心法院可能因为放弃Frye规则而轻信“垃圾科学”,但是最高法院在1993年的一个具有里程碑意义的案件中否认了这种主张。在Daubert v. Merrell Dow Pharmaceutical, Inc.一案中,法院全体一致的认为,Frye规则与联邦证据规则不能相容,且已经被后者的通过而取代。法院发现“有力的交叉询问、相反证据的呈递以及谨慎的(陪审团)指令是传统的、适当的攻击不可靠的但可采纳的证据的方法。”初审法院仍可以作出简易判决和指导性的陪审团裁决,但这不能充分显示证据的可靠性。

  Dauber一案对采纳联邦标准规则的州的影响还没有发现。然而,可以合理假定的是,在法院裁决专家证据具有相关性和可靠性之后,就DNA问题专家证据是可以采纳的。在这些管辖区域,被告将会很难排除DNA证据,虽然对它可采性的艰难挑战仍旧会不容怀疑的继续着,至少在不远的将来如此。Dauber一案对盛行Frye规则的州来说几乎没有任何影响。一些州甚至用最高法院的判决来肯定Frye规则。1994年10月,加利福尼亚州在Leahy案中确认了Frye规则。在这些州内,新的高等法院或者立法机关是改变证据可采性标准的唯一途径。

  立法上的可采性

  到1994年秋季,11个州通过法令要求在法庭上采纳DNA证据。马里兰州是第一个这样做的州,接着是明尼苏达州、路易斯安娜州和内华达州,它们都是在1989年通过的。大多数法律中都包含这样的语言,即,即使“没有专家证据的先例”,DNA鉴定是也是可接受的;它是一个“值得信赖的、可靠的方法”。有争议的是,这些法律都没有包含DNA分析方法,被告仍旧可以挑战实验室的工作和结果的统计解释。对于一个更加富有经验的被告来讲,律师可能会对DNA证据发动更多极其昂贵的挑战,对此,州立法机关很可能会以其他方式解决这一问题。

  专家证人

  一般而言,专家证人是他们所处行业中的佼佼者,专家证人经常被认为是用来攻击对方证词的“职业枪支”,专家证人的迅速扩大是刑事司法制度的一个显著发展。几乎没有任何种类的案件不受这些专家的影响,但是心理学、医学和DNA证据看起来会给他们带来很多的麻烦。很难下结论说一些人会乐于延伸或者忽略事实、歪曲科学以及成为“说谎者”。许多专家证人收入的很大一部分都来源于作证,在判定他们证词的可信性和重要性方面时,这应当作为一个因素被考虑进去。一个加利福尼亚州法官坦白地称他们为“学术福利制度”的受益者,并哀叹专家证人的使用。最近一篇有关于专家证人的道德和责任的文章中对专家证人提出下述资格标准:

  1、在相关专业领域具有本科和研究生学位;2、在与法医学相关的主体领域经历过专门的训练;3、在辩论学方面经受过一些训练;4、在专家学科内拥有职业团体要求的职业执照或者证明;5、在专业领域拥有实验、教学和出版的证明;6、先前拥有与作证问题直接相关的学科证明。

  其他帮助判定专家资格的因素包括:研究生训练、在同等评论性科学期刊上发表文章,对可接受的试验和程序的发展,在适当科学协会的成员资格或领导人员,以及最后,作为专家证人的经验。

  10年前,加利福尼亚People v. Brown一案的判决中增加了一条事后证明是很难适用的标准,即证人“还必须是公正无私的,也就是说,专家证人不能以个人态度接受一项技术,如果在相关的科学界这项技术还存在争论,而他的态度可能不是客观的”。证人也不应该毁损一项技术,夸大它在科学界的争论。也许获得公正无私的证人的最好方法是由法庭任命或者法庭支付专家证人的薪酬,而不是由当事人。这也是许多其他国家的实践。这种程序在美国还不是很通常,决定采用何种程序是各州和联邦法院的权力。涉及到DNA证据的一个很著名的案件是United States v. Yee,Eric Lander是该案的专家证人,他原来是数学家,后来成为一名遗传学家,它负责补充其他由控方和辩方召集的17个专家证人的证言。据报道,在辛普森案件的Kelly-Frye听证会上,法官Ito也召集了他自己的专家证人。

  辩论技巧

  辩方证人对DNA证据提出了各种各样的异议。他们不再试图怀疑这种技术本身。几年前,DNA鉴定赢得了广泛的接受并证实了它的可靠性,现在,反对者开始集中于两点进行攻击:(1)实验室工作的质量和方法论,包括实验室的误差率;(2)数据的统计学解释。随着时间的流逝,对DNA证据可采性攻击的焦点已经转变了。当一个焦点被否决时,DNA证据的反对者就会推出下一个焦点。争论和专家的质量和关联性都在下降,已经从人口遗传学家转移到生物统计学家,再到完全不相关的领域的统计学家。接下来的是最频繁听到的对DNA鉴定的抱怨摘要以及可能来自于法医学家对DNA鉴定的反应。

  利益冲突

  在DNA案件中,控方和辩方的专家证人是这一领域内最受争议和漠视的。几个法官评论说在Frye案中召开有关DNA的听证会是极端错误的。在诉讼和反诉讼中,争议的焦点是辩方证人因为利益冲突应该被取消作证资格。在某种特定的程度上,双方都是正确的。控方认为,在DNA听证会上辩方证人经常有一个既定的目的,即确保主题保持有争议,这样他们才能继续进行对他们有利的作证。而辩方经常认为,因为犯罪实验室和法律实施之间工作上的密切关系,开业的法医学家对辩方有一种固有的偏爱或倾向。实际上,刑事学家通常也是警察机关的雇员。

  如果法医学家是他们所在领域的领导者,他们可能会遭遇更进一步的利益冲突。如果他们发展或者发明新技术或者工具,他们可能在发展DNA鉴定方面拥有自己私人的利益。他们可能还对DNA实验室拥有股份,或者接受来自公共或私人机构的资金捐助。当然,陪审团有权了解所有的这些关系,这些关系也都应当被完全披露。同时,法院承认,“不能仅因为有学问的专家可以利用他们的技能谋生,就禁止采纳他们的意见。”这正如法院在最近的新泽西发生的一个案件中说的。

  样本的完整性

  辩方专家证人试图增加对DNA证据在搜集和鉴定方法上的怀疑,声称污染可能发生。通常的争论焦点是法医DNA鉴定的基础程序是在实验室中完成的,而实验室中采用的是纯净的和已知的样本,再次鉴定始终是一项选择权。虽然这是真实的,但是争论并没有提到污染后的通常结果,被检测到的容易,以及大多数法医DNA实验室的安全措施。

  在几乎所有的案件中,使用一个被充分污染的样本以改变鉴定结果的结果将会被裁决为非决定性的。样本可能被污染的一种途径是来源于进行分析操作的技术人员或者搜集证据的工作人员的遗传物质。对此,这不可能对被告有任何损害,因为这种违反操作规程的结果会被排除。最后,存在这样一种可能性,来源于疑犯的DNA可能偶然的与犯罪现场找到的DNA相混合。这样的偶然事件会产生错误的结果,尤其是当使用PCR扩大程序时。为了避免这种可能性,进行PCR试验的犯罪实验室会在隔绝的前提进行操作,在严格的情况下使污染的风险降到最小。

  不可否认,在分析混和样本和克服各种各样的污染物方面,DNA分析比其他鉴定要好的多。因为它的结构和相对稳定性,甚至在与酸、碱、汽油、石油或者漂白剂混和的情况下,DNA鉴定还是可以进行。

  误差率

  最新的反对理由是鉴定实验室的误差率,这也是辛普森案件中辩护队排除DNA证据的论据的核心。像法医学这样复杂的领域,有许多产生错误的来源,大多数都会导致不确定的或者没有结果。一个错误的正或负误差率是不可能衡量的,因为这些是很罕见的事件。这些是由人为误差或者故意导致的误差类型。应当注意,保管链上大多数类型的混淆或者失误都会导致假阳性的结果,这是对被告有利的。这在证据搜集到实验室之前更可能发生。没有任何误差率能够被接受。幸运的是,在DNA个案中,因为误差导致误判还没有被发现,虽然不可避免的在将来的某一天会出现。

  鉴定系统本身固有的误差,如不能精确的测量DNA限制酵素片段长度,可以由解释规则来很好的弥补,因为解释规则会考虑到这些种类的误差。并入该程序的一系列质量控制步骤也为个人和实验室的操作质量提供了良好的保证。在大多数案件中,在致命错误出现的很早之前,这些控制步骤就应该进行矫正性的行动了。

  将实验室误差最小化需要一个质量控制程序,如那些已经在法医实验室主动就位的程序。几乎所有的法医DNA实验室都参加了该程序,包括熟练鉴定以及确认最低操作水平已经被满足的程序。外部熟练鉴定还为实验室内部测量误差提供了时时比较程序。这些由美国犯罪实验室理事实验室鉴定合格董事会协会倡导的程序正在迅速传播。

  在法医学领域,质量的最后仲裁者是法庭,在法庭上,在询问和交叉询问下,专家证人提交他们的鉴定结果交给对方专家、法官和陪审团进行详细审查。为了确保鉴定工作的质量,额外的审查标准是必要的,包括个案审查、再鉴定和由对方专家就专门鉴定进行的检查。双方需要有权同等获取法庭的专门技术,以满足公平和正义的要求。

  群体遗传学评估

  在法庭DNA领域最有争议的辩论是使用统计学评估给定DNA图谱的稀有性。这个问题实际上是被期待解决,因为正是这些图谱的相当稀有才赋予了它们作为证据的决定性作用。这些遗传图谱的稀有性要依靠被检验的基因数目(通常是4或5个,或者更多)。每个基因结果的频率相乘得到一个合并的图谱频率或者最后呈现在法庭上的最后评估。

  批评者主张,在特定的种族群体中,可能会出现基因频率安排显著不同于在一般人群中发现的安排。他们声称用于频率统计的人口基数必须从嫌疑犯的特定基因库中获得。

特别推荐

地图
法律教育网官方微信

法律教育网微信公众号向您推荐考试资讯、辅导资料、考试教材、历年真题、法律常识、法律法规等资讯,只有你想不到,没有我们做不到!详情>>

1、凡本网注明“来源:法律教育网”的所有作品,版权均属法律教育网所有,未经本网授权不得转载、链接、转贴或以其他方式使用;已经本网授权的,应在授权范围内使用,且必须注明“来源:法律教育网”。违反上述声明者,本网将追究其法律责任。

2、本网部分资料为网上搜集转载,均尽力标明作者和出处。对于本网刊载作品涉及版权等问题的,请作者与本网站联系,本网站核实确认后会尽快予以处理。

本网转载之作品,并不意味着认同该作品的观点或真实性。如其他媒体、网站或个人转载使用,请与著作权人联系,并自负法律责任。

3、本网站欢迎积极投稿