| IN THE UNITED STATES DISTRICT COURT
FOR THE EASTERN DISTRICT OF PENNSYLVANIA
UNITED STATES OF AMERICA :
VS : CRIMINAL NUMBER 96-407-1
BYRON MITCHELL :
MEMORANDUM OF LAW IN SUPPORT OF MR.
MITCHELL’S MOTION TO EXCLUDE THE
GOVERNMENT’S FINGERPRINT IDENTIFICATION EVIDENCE
The government has failed to establish the scientific validity of the fingerprint identification evidence that it seeks to admit at Mr. Mitchell’s upcoming trial. Contrary to the government’s memorandum, the issue here is not the uniqueness and permanence of entire fingerprint patterns, consisting of hundreds of distinct ridge characteristics. Rather, the question is far more specific: Is there a scientific basis for a fingerprint examiner to make an identification, of absolute certainty, from a small distorted latent fingerprint fragment
, revealing only a small number of basic ridge characteristics such as the nine characteristics identified by the FBI examiner at Mr. Mitchell’s first trial. There are two fundamental premises that underlie such an identification: First, that two or more people cannot possibly share this number of basic ridge characteristics in common; and second, that fingerprint examiners can reliably assert absolute identity from small latent print fragments despite the unknown degree of distortion and variability from which all latent prints suffer. With the issue properly framed, it is readily evident that the government has failed to demonstrate the various indicia of scientific reliability set forth by the Supreme Court in Daubert v. Merrell Dow Pharmaceuticals
, 509 U.S. 579, 113 S.Ct. 2786, 125 L. Ed. 2d 469 (1993) and the Third Circuit in United States v. Downing
, 753 F.2d 1224, 1237-42 (3d Cir. 1985).
First, there has been no testing of either of the two fundamental premises that underlie the proffered identification. The failure to test these premises has been repeatedly recognized by various scientific commentators and it is demonstrated most clearly, in this case, by the lack of testing that is referred to in the government’s memorandum and exhibits.
Second, there is no known error rate for latent fingerprint examiners. The government’s claim that the error rate is “zero” is patently frivolous in light of the many examples of real life misidentifications that have occurred. It is also belied by the alarmingly high number of misidentifications that have occurred on latent print examiner proficiency exams.
Third, fingerprint examiners do not possess uniform objective standards to guide them in their comparisons. To the contrary, there is complete disagreement among fingerprint examiners as to how many points of comparison are necessary to make an identification, and many examiners now take the position that there should be no objective standard at all. As the government’s own expert, David Ashbaugh, acknowledges, a fingerprint examiner’s “opinion of individualization is SUBJECTIVE ” David Ashbaugh, Quantitative-Qualitative Friction Ridge Analysis: An Introduction to Basic and Advanced Ridgeology, 99 (Draft 1999) (Gov’t Ex. 10) (emphasis in original) [hereinafter Ashbaugh, Basic and Advanced Ridgeology].
Fourth, there is not a general consensus that fingerprint examiners can reliably make identifications on the basis of only nine matching characteristics. Many countries require that there be at least 12-16 points of comparison before fingerprint evidence is deemed sufficiently reliable so as to warrant its admission at a criminal trial.
Fifth, the professional literature of the fingerprint community confirms the scientific bankruptcy of the field. As the government’s expert acknowledges
, “it is difficult to comprehend a complete scientific review of friction ridge identification has not taken place during the last one hundred years[;] a situation seems to have developed where this science grew through default.” Ashbaugh, Basic and Advanced Ridgeology
, at 3 (Gov’t Ex. 10). Sixth, latent fingerprint identifications are analogous to other techniques, such as handwriting analysis and hair fiber comparisons, that federal courts, in the wake of Daubert
, have found to be scientifically unreliable. See Williamson v. Reynolds
, 904 F. Supp. 1529, 1558 (E. D. Okla. 1995); United States v. Starzecpyzel
, 880 F. Supp. 1027, 1037 (S.D.N.Y. 1995).
Seventh, latent fingerprint identifications do not have any non-judicial applications. The use of fingerprints has been under the “control of the police community rather than the scientific community” and latent prints are used by law enforcement solely as a “tool for solving crime.” Ashbaugh, Basic and Advanced Ridgeology, supra, at 3 (Gov’t Ex. 10).
In addition to these various Daubert
factors, the lack of scientific reliability of the government’s fingerprint evidence has been most dramatically demonstrated by a test that the government performed specifically for purposes of this litigation. In an apparent effort to demonstrate that different fingerprint examiners will, at least, be able to reach the same conclusion when they are presented with the same data, the government provided the two latent prints at issue in this case, along with Mr. Mitchell’s inked prints, to 53 different law enforcement agencies. Contrary to the government’s expectations, however, 23% of the responding agencies found that there was an insufficient basis to make an identification with respect to one of the two latents and 17% found an insufficient basis as to the other. The government’s experiment thus perfectly illustrates how subjective latent print identifications really are and how unreliable their results can be.
Finally, the unreliability of latent fingerprint identifications has already been judicially recognized. In the only known fingerprint case in which a federal trial court has performed the type of analysis that is now mandated by Daubert, the district court excluded the government’s fingerprint identification evidence, finding that there was no scientific basis for the latent print examiner’s opinion of identification. United States v. Parks (C.D. Cal. 1991) (No. CR-91-358-JSL) (Ex. 48). The district court in Parks reached its determination after hearing from three different fingerprint experts produced by the government in an effort to have the evidence admitted. In excluding the evidence, the district court recognized, among other things, the lack of testing that has been done in the field, the failure of latent fingerprint examiners to employ uniform objective standards, and the minimal training that latent print examiners typically receive.
Accordingly, for all of the foregoing reasons, Mr. Mitchell requests that this Court preclude the government from introducing its fingerprint identification evidence at his upcoming trial. In the event, however, that the Court allows the government to admit the fingerprint evidence, Mr. Mitchell respectfully requests the opportunity, consistent with the Third Circuit’s decision in United States v. Velasquez, 64 F.3d 844 (3d Cir. 1995), to introduce expert witness testimony regarding the deficiencies of the government’s evidence.
1. Fingerprint Fundamentals Which the Government Neglected to Mention In ItsMemorandum
An average human fingerprint contains between 75 and 175 ridge characteristics. An Analysis of Standards in Fingerprint Identification
, FBI L. Enforcement Bull., June 1972, at 1 (Ex. 1) [hereinafter FBI, Fingerprint Identification
]. These ridge characteristics generally consist of a few different types, although there is no standard agreement among fingerprint examiners as to either the precise number or nomenclature of the different characteristics. James F. Cowger, Friction Ridge Skin: Comparison and Identification of Fingerprints
at 143 (1983) (“The terms used to define and describe these characteristics vary markedly among writers in the field and differ even among examiners depending upon the organization in which they were trained.”). The ridge characteristics most commonly referred to are: 1) islands, also referred to as dots
, which are single independent ridge units; 2) short ridges, in which both ends of the ridge are readily observable; 3) ridge endings, where a ridge comes to an abrupt end; 4) bifurcations, in which the ridge forks into two; 5) enclosures, which are formed by two bifurcations that face each other
; 6) spurs, where the ridge divides and one branch comes to an end; and 7) cross-overs, in which a short ridge crosses from one ridge to the next. John Berry, The History and Development of Fingerprinting, in Advances in Fingerprint Technology
at 2 (Henry C. Lee & R. E. Gaensslen eds., 1994); Ashbaugh, Basic and Advanced Ridgeology
, at 94, 95 (Gov’t Ex. 10) (illustrations of these various characteristics are provided as Defense Exhibit 2).
While some occasional research has been done with respect to the relative frequencies with which these and other characteristics occur, no weighted measures of the characteristics have ever been adopted by fingerprint examiners on the basis of these studies. Research
, moreover, has shown that different fingerprint examiners hold widely varying opinions regarding which characteristics appear most commonly. James W. Osterburg, An Inquiry Into the Nature of Proof
, 9 J. of Forensic Sci. 413, 425 (1964) (Ex. 3) (“Clearly subjective evaluation of the significance to be attached to a fingerprint characteristic is suspect.”).
All prints, both inked and latent, are subject to various types of distortions and artifacts. David Ashbaugh, The Premises of Friction Ridge Identification, Clarity, and the Identification Process, 44 J. of Forensic Identification 499, 513 (1994) (Ex. 4) [hereinafter Ashbaugh, Premises]. The most common type being pressure distortion which occurs when the print is being deposited. Id. Other types of distortion can be caused by the shape of the surface on which the print has been deposited and by the mediums used to develop and lift the print. Ashbaugh, Basic and Advanced Ridgeology, supra, (Gov’t Ex. 10 at 94-95). Significantly, distortion can cause a ridge characteristic to appear as something other than what it really is. Id. at 82; David A. Stoney & John I. Thornton, A Critical Analysis of Quantitative Fingerprint Individuality Models, 31 J. of Forensic Sci. 1187, 1193 (1986) (Ex. 5). For example, powder used to lift a latent print may cause a ridge ending to appear as a bifurcation. Ashbaugh, Basic and Advanced Ridgeology, supra, (Gov’t Ex. 10 at 82). There have been no studies done to determine the frequency with which such distortions occur.
Latent print examiners make identifications when they find a certain number of ridge characteristics to be in common, both in terms of type and location, on the two prints that they are comparing.1
FBI, Fingerprint Identification
(Ex. 1). As discussed further below
, there is considerable disagreement among latent print examiners as to how many common characteristics should be found before an identification is made. Many examiners currently believe that there should be no minimum standard whatsoever and that the determination of whether there is a sufficient basis for an identification should be left entirely to the subjective judgment of the individual examiner.
It has been well documented that different people can share a limited number of fingerprint ridge characteristics in common. Exhibit 6, for example, is an article that discusses fingerprints from two different people that contain seven matching ridge characteristics. Likewise, Exhibit 7 is a textbook reference to fingerprints from different individuals that have ten characteristics in common. There have been no scientific studies performed that can reasonably serve to predict the probability of such events occurring.
Lacking any such probability studies, latent print examiners do not offer opinions of identification in terms of probability. Indeed, latent print examiners are actually prohibited from doing so by the rules of their primary professional association, the International Association of Identification (IAI) (Ex. 8). Instead, latent print examiners make the claim of “absolute certainty” for their identifications. Examiners provide an opinion that the latent print at issue was made by a particular finger to the exclusion of all other fingerprints in the world. Such assertions of absolute certainty, however, are inherently unscientific. Here is what one of the government’s own experts has had to say on this issue:
Imposing deductive conclusions of absolute certainty upon the results of an essentially inductive process is a futile attempt to force the square peg into the round hole. This categorical requirement of absolute certainty has no particular scientific principle but has evolved from a practice shaped more from allegiance to dogma than a foundation in science. Once begun, the assumption of absolute certainty as the only possible conclusion has been maintained by a system of societal indoctrination, not reason, and has achieved such a ritualistic sanctity that even mild suggestions that its premise should be re-examined are instantly regarded as acts of blasphemy. Whatever this may be, it is not science.
David Grieve, Possession of Truth
, 46 J. of Forensic Identification 521, 527-28 (1996) (Ex. 9).
2. The Fingerprint Identification at Issue in the Case at Bar: How Many Points of Similarity Are There?
The government contended at Mr. Mitchell’s first trial that two latent fingerprints lifted from the robbers’ getaway car matched inked prints that were taken of Mr. Mitchell’s left and right thumbs. The government’s fingerprint expert at trial, FBI agent Dwayne Johnson, identified what he believed to be nine points of similarity between one of the two latents and the inked print of Mr. Mitchell’s right thumb. A photographic copy of the charts that agent Johnson used to illustrate these common points is provided as Exhibit 10. As to the other latent print, Agent Johnson provided no explanation whatsoever to support his opinion that it had been made by Mr. Mitchell’s left thumb.
Agent Johnson conceded during his testimony that he had never heard of a fingerprint examiner making an identification on the basis of less than seven points of similarity and that he himself had never done so. (Ex. 11 at 1, 2). Johnson also conceded that the latent prints at issue were somewhat “eroded” and that the conclusion that he had reached was “subjective.” (Ex. 11 at 3-5). A cursory examination of Exhibit 10 will readily reveal just how debatable some of the points identified by Johnson actually are. Indeed, as discussed further below, there has been considerable disagreement among the law enforcement fingerprint examiners who have subsequently examined these prints, at the government’s request, as to just how many points of comparison can reasonably be seen and as to whether there is a sufficient basis to make an identification.
Moreover, even assuming arguendo, that Agent Johnson correctly identified each of the common ridge characteristics, these characteristics are hardly unique to Mr. Mitchell. As Johnson explained during his testimony, points 1, 2, 4, 5, 6 are basic bifurcations and point number 3 is a simple ridge ending. (Ex. 11 at 6-9).2 Johnson, however, did not advise the jury that bifurcations and ridge endings are basic ridge characteristics that virtually every human being in the world possesses.
Johnson also failed to explain that the opposing bifurcations indicated at points 5 and 6 actually constitute a single characteristic, namely an enclosure. The same is true for points 7 and 8. The International Association of Identification, the leading professional association for fingerprint examiners, has declared in an official report that an enclosure should be counted as a single point rather than as two separate bifurcations. Robert Olsen, Friction Ridge Characteristics and Points of Identity: An Unresolved Dichotomy of Terms, 41 J. of Forensic Identification 195 (1991) (Ex. 12). Accordingly, what agent Johnson has counted as nine characteristics is in reality only seven.
3. The Legal Standard to be Applied
In Daubert v. Merrell Dow Pharmaceuticals, Inc.
, 509 U.S. 579, 113 S. Ct. 2786 (1993), the Supreme Court held that federal trial courts, when faced with a proffer of expert scientific testimony
, must determine at the outset whether the “reasoning or methodology underlying the testimony is scientifically valid . . . .” Id.
at 592-93, 113 S. Ct. at 2796. As the Court recognized, in a case involving scientific evidence, evidentiary reliability will be based upon scientific validity. Id.
at 590 n.9, 113 S. Ct. at 2795 n.9. This standard applies both to “novel scientific techniques” and to “well established propositions.” Id.
at 592 n.11, 113 S. Ct. at 2796 n.11.
The Daubert Court suggested five factors that trial courts may consider in determining whether proffered expert testimony is scientifically valid. The first factor is whether the “theory or technique . . . can be (and has been) tested.” Id. at 593, 113 S. Ct. at 2796. As the Court recognized, empirical testing is the primary criteria of science:
Scientific methodology today is based on generating hypotheses and testing them to see if they can be falsified; indeed, this methodology is what distinguishes science from other fields of human inquiry. The statements constituting a scientific explanation must be capable of empirical test. The criterion of the scientific status of a theory is its falsifibility, or testability.
Id. at 593, 113 S. Ct. at 2796-97 (internal quotations and citations omitted).
A second closely related factor that the Daubert Court suggested should “ordinarily” be considered is the “known or potential rate of error” of the particular technique. Id. at 594, 113 S. Ct. at 2797. In this regard, the Court cited the Seventh Circuit’s decision in United States v. Smith, 869 F.2d 348, 353-354 (7th Cir. 1989), in which the Seventh Circuit surveyed studies concerning the error rate of spectograghic voice identification techniques. Id.
A third factor pointed to by the Court is the “existence and maintenance of standards controlling the technique’s operation.” Id.
As an example, the Supreme Court cited the Second Circuit’s opinion in United States v. Williams
, 583 F.2d 1194, 1198 (2d Cir. 1978), in which the Second Circuit observed that the “International Association of Voice Identification . . . requires that ten matches be found before a positive identification can be made.” Id.
Fourth, the Daubert Court held that “general acceptance can . . . have a bearing on the inquiry.” Id. “A reliability assessment does not require, although it does permit, explicit identification of a relevant scientific community and an express determination of a particular degree of acceptance within that community.” Id. (quoting United States v. Downing, 753 F.2d 1224, 1242 (3d Cir. 1985)). As the Court recognized, “widespread acceptance can be an important factor in ruling particular evidence admissible and a ‘known technique which has been able to attract only minimal support within the community’ . . . may properly be viewed with skepticism.” Id. (quoting Downing, 753 F.2d at 1238)).
Finally, the Daubert Court recognized that an additional factor which may be considered “is whether the theory or technique has been subjected to peer review and publication.” Id. at 593, 113 S. Ct. at 2797. As the Court recognized, “submission to the scrutiny of the scientific community is a component of ‘good science,’ in part because it increases the likelihood that substantive flaws in methodology will be detected.” Id. Accordingly, “[t]he fact of publication (or lack thereof) in a peer reviewed journal . . . [is] a relevant, though not dispositive, consideration in assessing the scientific validity of a particular technique or methodology on which an opinion is premised.” Id. at 594, 113 S. Ct. at 2797.3
In providing the above factors
, the Supreme Court emphasized that the inquiry under Federal Rule of Evidence 702 is a “flexible one”and that, as such, additional factors may be considered. Id.
Several such additional factors have been suggested by the Third Circuit:
(1) the relationship of the technique to methods which have been established to be reliable;
(2) the qualifications of the expert witness testifying based on the methodology;
(3) the non judicial uses to which the method has been put
United States v. Downing
, 753 F.2d 1224, 1238-39 (3d Cir. 1985); see also In re Paoli R.R. Yard PCB Litig.
, 35 F.3d 717, 742 n.8 (3d Cir. 1994).
As demonstrated below, the government’s proposed fingerprint identification evidence fails with respect to each and every factor that has been identified by the Supreme Court and the Third Circuit.4
4. The Government Has Failed to Satisfy the Daubert and Downing Factors
A. The Failure to Test the Fundamental Hypothesis Upon Which Latent Print Identifications Are Based
The proffered fingerprint identification evidence in this case fails the most basic criteria of science: The premises underlying the identification have not been tested to determine if they can be falsified. As discussed above, there are two fundamental premises to a latent print identification of the type at issue here: First, that it is impossible for two or more people to have prints showing a limited number of ridge characteristics in common such as the seven/nine characteristics identified by the FBI fingerprint examiner in the case at bar, and second, that latent fingerprint examiners can reliably make identifications from small distorted latent fingerprint fragments that reveal only a limited number of basic ridge characteristics.
That these premises have not been empirically validated has, in the wake of Daubert, been repeatedly recognized by forensic science experts. See Michael J. Saks, Merlin and Solomon: Lessons from the Law’s Formative Encounters With Forensic Identification Science, 49 Hastings L.J. 1069, 1105-06 (1998) (Ex. 13) (“Although in principle fingerprint identification depends upon an objective, probabilistic inquiry, its practitioners use no probability models and have no probability data to use[;] they rely on intuitions and assumptions that have not been tested rigorously . . . .); Margaret A. Berger, Procedural Paradigms For Applying the Daubert Test, 78 Minn. L. Rev. 1345, 1353 (1994) (Ex. 14) (“Considerable forensic evidence [such as fingerprinting] made its way into the courtroom without empirical validation of the underlying theory and/or its particular application.”).
The lack of testing has also been recognized by those within the fingerprint community. David Stoney, a leading scholar and fingerprint practitioner, has written:
[T]here is no justification [for fingerprint identifications] based on conventional science: no theoretical model, statistics or an empirical validation process.