641.1Footprints, Shoeprints, & Tire Tracks
- A properly qualified witness can examine the distinguishing marks and features of a shoeprint, footprint, or tire track impression and express an opinion about whether it is a match to, or consistent with, a sample connected to the defendant.
- A witness may also be permitted to give a lay opinion regarding readily observable characteristics of the impression, such as a distinctive tread pattern.
- Expert testimony on these types of comparisons has historically been allowed in North Carolina, and federal courts applying the Daubert standard have likewise allowed it into evidence, but some critics have questioned the accuracy and reliability of the discipline.
Overview and Methodology
At every crime scene, the perpetrator has usually come and gone either by foot or by car, leaving behind various types of evidence. Shoeprints, footprints, and tire tracks are often inadvertently destroyed at the crime scene by bystanders or law enforcement officers investigating the crime who simply walk over the impressions left by the defendant – but if the impressions or prints are preserved and properly collected, a latent evidence analyst can use these impressions and compare them for a match to a known shoeprint, footprint, or tire connected to the defendant. If the two prints are found to be similar, that comparison may be introduced into evidence to support the identification of the defendant as the perpetrator of the crime, because the evidence tends to connect the defendant with that crime. See State v. Williams, 308 N.C. 47 (1983); State v. Jackson, 302 N.C. 101 (1981).
There are two main areas of comparison:
Friction Ridge Details
If the impression submitted to the laboratory for comparison is made by the bare soles or toes of someone’s foot, the ridge detail of the barefoot impression can be examined for points of identification in the same way that fingerprint impressions are analyzed. See State v. Rogers, 233 N.C. 390 (1951).
Size, Design and Deterioration Details
When examining a shoeprint or tire track, the analyst must have enough information to determine the size and design of the shoe or tire tread in order to make an identification. If the footprint, shoeprint, or tire track impression reveals details of minute cuts, gouges, and distinctive signs of wear and tear (sometimes called “randomly acquired characteristics”) that are consistent in location and degree with similar details found on defendant’s known sample, then the analyst may be able to make a more positive identification. The analyst’s degree of certainty will depend on the number and clarity of those impression details. The degree of certainty of identification for the analyst’s opinion may range from “not a match” to “the defendant could have made this impression” to “the defendant’s shoe or tire positively did make this impression.”
Foundation and Admissibility
Expert testimony about shoeprint, footprint, or tire track evidence has historically been admitted in North Carolina courts, after laying a proper foundation and establishing the witness’s qualifications. See, e.g., State v. Williams, 308 N.C. 47 (1983) (noting that an SBI Agent was accepted as an expert witness and testified extensively concerning the unique characteristics of the tread on the shoes taken from the defendant and the shoe prints found at the scene of the crime); State v. Bullard, 312 N.C 129 (1984) (“Dr. Robbins was clearly in a superior position and better qualified to compare the bloody bare footprint found on the bridge with those of the defendants. The expertise to make the comparisons involved a certain knowledge which was beyond the realm of that of the average juror.”).
Evidence of shoeprints or other tracks left at the crime scene that corresponds to those of the defendant may be admitted as relevant for the purpose of connecting the defendant with the crime – that is, to identify the defendant as the perpetrator. State v. Jackson, 302 N.C. 101 (1981). The length of time between when the crime occurred and when the shoeprint or tire track evidence was collected affects the weight of the evidence, not its admissibility. In other words, this type of testimony has been deemed relevant and admissible for purposes of identifying the defendant as the perpetrator, even if it cannot be conclusively determined when the print or impression may have been left. See State v. Pratt, 306 N.C. 673 (1982) (opinion testimony that defendant’s tennis shoes were the same shoes that had made impressions in the sand near the crime scene was properly admitted, even though there was no evidence showing when the footprints were made and the footprints were discovered several hours after the assailant’s encounter with the victims); State v. Adcox, 303 N.C. 133 (1981) (court rejected defendant’s argument that passage of 33 days from time of crime to seizure of shoes, and state’s failure to tie ownership of shoes directly to defendant, made evidence inadmissible).
Questions about the science
Notwithstanding the long history of allowing this type of evidence in North Carolina courts, and recent federal decisions that have continued to find it reliable and admissible under the Daubert standard, prosecutors should make sure that the witness is prepared to offer a satisfactory response to recent criticisms about the reliability of this field and its methods. For example, the President’s Council of Advisors on Science and Technology (“PCAST”) 2016 report, Section 5.6, pages 114-117, found there were “no appropriate empirical studies” to support the analysis, and in the absence of such testing or error-checking, the results lacked scientific validity. Before admitting the expert’s opinion, the trial judge will have to find that the testimony “is the product of reliable principles and methods” under Rule 702(a)(2).
There are no post-2011 North Carolina appellate cases directly analyzing the admissibility of shoeprint, footprint, and tire track evidence under the revised Rule 702 incorporating the Daubert standard. However, several federal courts applying the Daubert standard have continued to allow expert testimony on these subjects at trial. See, e.g., U.S. v. Ford, 481 F.3d 215 (3d Cir. 2007) (trial court “exercised its gatekeeping function” and “determined that the testimony was based on a reliable methodology,” so it “properly found that the expert shoeprint testimony was based on valid specialized knowledge and would aid the jury in making comparisons between the soles of shoes” found at the scene and those found on the defendant); U.S. v. Allen, 390 F.3d 944 (7th Cir. 2004) (applying Daubert, and finding that district court did not abuse its discretion by “admitting expert testimony by Fort Wayne Police Forensic Examiner Thomas Pitzen regarding shoe print evidence”); U.S. v. Mahone, 328 F. Supp. 2d 77 (D. Me. 2004), aff'd, 453 F.3d 68 (1st Cir. 2006) (analyzing admissibility factors and concluding that “proffered expert footwear impression testimony is admissible under the standards set forth both in Rule 702 and Daubert”); see also U.S. v. Barnes, 481 Fed. Appx. 505 (11th Cir. 2012) (unpublished) (testimony by boot print expert “used methodologies that did not allow for quantification, but that were generally accepted” and satisfied Daubert).
Lay Witness Opinion
A lay witness may also be allowed to testify about identification of shoeprints or other tracks, as long as the testimony is based on the witness’s own observations. See State v. Jackson, 302 N.C. 101 (1981) (non-expert properly permitted to testify about similarity between design on sole of shoes taken from defendant and the design observed in shoeprints found at crime scene); State v. General, 91 N.C. App. 375 (1988); State v. Plowden, 65 N.C. App. 408 (1983).
On the other hand, if the witness’s opinion testimony is no more probative than what the jurors can just as easily see and decide for themselves, the court may not allow the witness to express an opinion. See State v. Fulton, 299 N.C. 491 (1980) (error to allow non-expert police officer to give his opinion that the tread design shown in a photograph of shoe tracks found near a crime scene was the same as the tread design of defendant’s shoes, because the jury was just as well qualified to draw inferences and conclusions from the facts related in witness’s opinion testimony – but error was harmless).
Explaining the opinion
If the lay witness is not permitted to give an opinion regarding a “match,” the prosecutor should still ask the witness to explain all the factors which formed the basis for reaching that opinion, so that the jurors can reach the same conclusion on their own.
For example, did the witness compare the length of the print vs. the length of the sample shoe – what was the result? Do the tread patterns on both soles show equal spacing and design – how was that measured? Were there any distinctive cuts, marks, gouges or wear patterns that appear on both the tracks and the defendant’s shoes – point those out to the jury.
There are four main methods of collecting evidence of shoeprint, footprint, or tire track:
If possible, the object on which the impression is found may be entirely removed (e.g., by removing a piece of flooring). This is generally used when residue is found from someone who stepped or drove in mud, soil, paint, or blood and then left behind a “visible print.”
An officer or analyst can make a cast of the impression using plaster or similar material. This method is usually used when an impression is left in a soft material such as sand or soil.
On harder and smoother surfaces, an officer or analyst can dust for details of shoe, boot, or barefoot sole impression, similar to dusting for fingerprint impressions.
A photograph of the impression is generally used in addition to one of the other methods described. A scale of measurement (e.g., a ruler) should be included in the impression photograph in order to make 1:1 scale photographic enlargements.