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Evidence Expert Testimony Essay

In bank robbery trial, admitting under FRE 702 expert FBI analyst testimony that a shoe worn by the defendant at the time of his arrest had left a partial impression on a piece of paper at the bank counter where the defendant allegedly jumped during the charged robbery, admitting expert testimony based on use of a "precise four-step methodology" employed by over 30 other countries, in United States v. Smith, 697 F.3d 625 (7th Cir. Oct. 4, 2012) (Nos. 11-2128, 11-2398)

The Federal Evidence Blog has assessed the reception of shoe print testimony for purposes of identification. In a 2009 blog essay, "Shoeprint Expert Testimony Satisfied Daubert Reliability Factors," we noted a Third Circuit finding that shoe print evidence can be sufficiently reliable, even if there is a "lack of precision in a shoeprint." This lack of precision did not render the evidence inadmissible and seemed to go only to the weight of the evidence. A recent Seventh Circuit Case examines some of the same difficulties in admitting shoe print expert evidence.

In the Seventh Circuit case, defendant Smith was arrested with others and charged with bank robbery and possession of a firearm in furtherance of a crime of violence. As recounted by a cooperating co-defendant's testimony at trial, after defendant's entry into the bank the defendant "vaulted over the [teller] counter, leaving a shoe print on a piece of paper" as he did so. At the time of the robbery, the defendants had been under FBI surveillance involving a series of robberies occurring in the neighborhood. The agents had been able to track the defendant's movements fleeing from the bank and ultimately apprehended the defendants. Upon his trial for the robbery, the defendant was convicted and he appealed, contending that the trial court improperly admitted identification testimony by an FBI shoe analyst. That analyst explained to the court the science of tying shoes (the ones in which the defendant was arrested) with the shoe print the bank robber had left from vaulting over the teller counter.

As part of his case, the defendant sought to prevent the admission of identification evidence based on analysis of his shoes with shoe marks impressions left by the perpetrators of the robbery. In conducting a Daubert hearing on the admission of this evidence, the circuit carefully noted the protocol used by the analyst as set forth in the witness's testimony: The expert relied on a "four-step methodology" to compare footprints with a particular suspect's shoes. This methodology involved considering a chain of four succeeding questions:

  1. Print Assessment: [I]f there was sufficient detail in the questioned impression (i.e., the one recovered from the bank) and then he compared the design (e.g., a series of diamonds or circles) of the questioned impression on the outsole (or bottom of the shoe) with the design on the outsole of the known shoes.
  2. Relative Size: If the design of the questioned impression and that of the known shoe were the same, he determined if the physical sizes (i.e., the outside dimensions, length, and width) and spatial relationship of the design features corresponded;
  3. Wear Features: If the design and size were the same ...analy[ze] whether there were wear features in the questioned impression (e.g., portion of design elements such as a logo worn off) that were also in the known shoe; and
  4. Identifying Characteristics: If the design and size were the same and there was wear correspondence, he looked for any identifying characteristics on the questioned impression and the known shoe, such as rocks or glass or nicks, cuts, or gouges that may appear on the bottoms of the shoes.
Smith, 697 F.3d at 633.

The description of this standard protocol was only part of the FBI expert's Daubert qualification. The expert provided additional information about the acceptance of the methodology in the field, an assessment of the facts used in the witness's analysis, and the application of "the principles and methods reliably to the facts of the case." The defendant contended that the proffered expert testimony on shoe identification "does not meet the demands of Rule 702." The Seventh Circuit took the opportunity to explain why such expert opinion testimony could be admitted:

[T]oday [we] reaffirm our holding in" United States v. Allen, 390 F.3d 944 949-50 (7th Cir. 2004), which "affirmed the admission of footprint analysis testimony where the expert testified that “accurate comparisons require a trained eye; the techniques for shoe-print identification are generally accepted in the forensic community; and the methodologies are subject to peer review.” Allen, 390 F.3d at 949–50. In this case, FBI Examiner Smith testified that the four-step approach he used is used by forensic laboratories throughout the United States, in Canada, and in thirty other countries. He also explained that there have been peer reviews of the methodology he used published in several books and articles. And FBI Examiner Smith explained in detail how he applied this methodology to the footprint impressions recovered at the bank. Thus, Smith's testimony was based “upon sufficient facts,” was the “product of reliable principles and methods,” and his testimony established that he “applied the principles and methods reliably to the facts of the case.” Accordingly, consistent with our holding in Allen, we conclude that the district court did not abuse its discretion in admitting FBI Examiner Smith's expert testimony regarding the shoe print evidence.
Smith, 697 F.3d at 634-35.


The First Circuit noted that a number of other circuits seemed to agree with this approach to foot ware expert testimony, citing the following case examples of the broad agreement:

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Unformatted text preview: HAIR TESTIMONY ESSAY After completion of Hair Lab #2 I am an expert in Forensic Hair Analysis. I have been working in the FBI for over 20 years, studying hairs under the microscope, so it is not very often that I am incorrect in my assumptions. I am here today to help discuss a most peculiar case regarding a mysterious hair sample found on the crime scene. A woman was found bludgeoned to death by a blunt object, and tied up by a rope underneath her bed. After extensive observations made regarding the body, my team and I came across a short strand of hair on the woman’s pant leg, that we found did not match her own hair. It was not much—but it was enough to quickly rule out 15 of the 17 subjects we had suspected. Before I continue, I must first explain the different parts of a hair shaft, and how it is very important to look at the details in each one to try to determine unique qualities about that hair. The different parts of a hair shaft are as labeled below: The cuticle is the outermost layer of the hair. Oftentimes, the thickness of the cuticle can help rule out suspects due to a defining characteristic that it may have (ex. the left side is significantly thinner than the right side). The cortex is the middle layer between the cuticle and the medulla. In the cortex, you see the pigment (the color) of the hair. This can quickly eliminate the suspects with differently colored hair. Though it might be difficult to see clearly, the scale pattern pictured on the hair shaft above on the right, can significantly narrow down a search for a suspect, because the scale patterns are all unique, in a similar fashion to a fingerprint. Finally, the medulla is the innermost layer of the hair shaft. It is easiest, perhaps, to notice a defining characteristic in the medulla, given that it is, indeed, present. In most cases, the medulla will be severely fragmented, in a similar way to the photo above. However, it is possible that there will be a full medulla that runs throughout the entire hair shaft, or even no medulla at all. Though it may not seem like it, both these photos are of the same hair sample; in fact, they are photos of the unknown hair sample found on the crime scene by my team, enlarged under a microscope. After doing extensive research, and collecting hair samples from 17 suspects, my team and I narrowed our search down to two samples. Hair sample #1, and hair sample #15. Both these samples had a similar color to the unknown sample, as well as a moderately thick cuticle and a very fragmented medulla. Pictured below are hair samples #1 (left) compared to the unknown hair sample (right) at several power magnifications underneath the microscope. Hair Sample #1, power 4x Hair Sample unknown, power 4x Hair Sample #1, power 10x Hair Sample unknown, power 4x Hair Sample #1, power 40x Hair Sample unknown, power 40x Hair sample #1 looks very similar to the unknown hair sample, however, my team and I did notice three characteristics that was mismatched—the pigment, the medulla fragmentation and the scale pattern. Clearly visible in the first 2 photos (power 4x), the pigmentation in the unknown hair changes from dark (bottom) to light (top), suggesting that the hair was dyed in an ombre style. Hair sample #1, however, was a consistent color throughout the shaft. In addition, the medulla fragments were much longer in the unknown sample, and quite short and spotty in sample #1. Finally, the last 2 photos show the scale pattern (40x magnification). While sample #1 has quite jagged, uneven scales, the unknown sample has smoother, straighter scales that that travel through the width of the hair. Based on these observations, we ruled out sample #1 as the culprit. All that was left to do, was prove that the owner of hair sample #15 was, indeed, the culprit. Pictured below are hair samples #15 (left) compared to the unknown hair samples (right) at several power magnifications underneath the microscope. Hair Sample #15, power 4x Hair Sample unknown, power 4x Hair Sample #15, power 10x Hair Sample unknown, power 10x Hair Sample #15, power 40x Hair Sample unknown, power 40x As seen clearly in the first 2 photos (4x), both sample #15 and the unknown sample have ombre colored hair, where the pigment changes its gradient throughout the hair. If that already wasn’t enough evidence, the medulla fragments are roughly the same length and the same thickness. The color looks a bit darker in the photos under 10x magnification, however we have concluded that this is only because the microscope was set on a higher exposure when we took the unknown sample, making the hair look lighter. Finally, looking at the scale pattern under a magnification of 40x confirmed our suspicions. As the two photos are set on the same exposure under the microscope, it is obvious that they are the exact same thickness and color. That being said, we can confirm that hair sample #15 matches the unknown hair sample found on the victim’s body. The process of finding a culprit was a long and tedious one, in which my team and I had to carefully analyze multiple hair samples to look for similarities to the unknown sample. Hair is not individualizing evidence, but rather class evidence, meaning that there is no one characteristic that can be identified as having originated from a particular person or source. This makes finding a culprit more difficult because every single feature on a suspect’s hair sample had to be identical to the unknown sample. Lucky for us, that was exactly the case with sample #15. As an expert witness and forensic hair analyst, I conclude that the hair sample found on the crime scene belonged to suspect #15. ...
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