Court Filing
Filed: 04/18/2025 10:25:44 Fourth Judicial District, Ada County Trent Tripple, Clerk of the Court
By: Deputy Clerk-Waters, Renee
IN THE DISTRICT COURT OF THE FOURTH JUDICIAL DISTRICT OF
THE STATE OF IDAHO, IN AND FOR THE COUNTY OF ADA
STATE OF IDAHO,
Plaintiff, Ada County Case No. CR01-24-31665
V.
ORDER ON DEFENDANT'S MOTION IN
BRYAN C. KOHBERGER, LIMINE RE: RYLENE NOWLIN AND
' TOUCH ' AND ' CONTACT ' DNA
Defendant.
I. INTRODUCTION
Defendant moves in limine to exclude the testimony of Rylene Nowlin, the Lab Manager with the Idaho State Police Forensic Services Laboratory who was disclosed by the State to testify about " touch " DNA and the transfer of DNA generally and, more specifically, that the DNA located on the knife sheath was more likely the result of a direct transfer. Defendant argues that Ms. Nowlin's testimony, as well as any other testimony referencing the terms " touch " or " contact " DNA and / or purporting to be an opinion about the means or mechanism how the DNA ended up on the knife sheath, is irrelevant or impermissible under IRE 403 and fails to satisfy IRE 703.
Oral argument on the motion was held on April 9, 2025, after which the Court took the matter under advisement. The Court does not find exclusion of Ms. Nowlin's opinions is warranted. However, the Court requests that the parties instruct their witnesses to avoid use of terms " touch DNA ", " contact DNA " and " trace DNA. "
II. STANDARDS
The admissibility of expert opinion testimony is discretionary. State v. Almaraz, 154 Idaho 584, 590, 301 P.3d 242, 248 (2013). Likewise, whether to exclude evidence under IRE 403 is discretionary. State v. Rambo, 173 Idaho 272, 281, 540 P.3d 974, 983 (2023). On these discretionary matters, the trial court must: 1) correctly perceive the issue as one of discretion; 2) act within the boundaries of such discretion; 3) act consistently with any legal standards applicable to the specific choices before it, and; 4) reach its decision by an exercise of reason. Id.
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III. FACTS
A knife sheath was recovered from the crime scene in this matter and swabbed for DNA.
A sample of DNA, identified as Q1.1, was extracted from the swab by the Idaho State Police Forensics Lab (" ISP Lab "). The DNA concentration was 0.168 mg / uL. It was subsequently tested using standard DNA STR (Short Tandem Repeat) methods. The STR profile developed revealed that the DNA came from a single source male profile.
The State disclosed Rylene Nowlin, the Lab Manager for the ISP Lab to testify to the operations of a forensic laboratory, the structure of the ISP Lab and the types of evidence it processes. Her disclosure further states:
Ms. Nowlin will also testify to touch DNA and transfer of DNA. Specifically, Nowlin will testify to the characteristics and nature of touch DNA, including how it is deposited and transferred to an item of evidence; the methods used to collect and preserve touch DNA samples from items of evidence; the procedures and protocols used by forensic scientists to extract and analyze touch DNA; the manner in which results from touch DNA samples are interpreted; and the reliability of touch DNA analysis and its acceptability in the field of forensic science. Nowlin will also testify to the potential for DNA to transfer between an individual and an object (s), including the distinction between primary and secondary transfer and the factors influencing the likelihood of transfer.
State's Exhibit S-21 (Nowlin Initial Discl.) ¹ On February 17, 2025, the State submitted its rebuttal disclosures including one from Ms.
Nowlin. The focus of the second disclosure is touch / contact DNA and direct versus indirect transfer, including factors that can influence the transfer and persistence of DNA on an item. The final paragraph of her rebuttal disclosure states:
Many complicated factors can influence the likelihood of transfer of DNA and the persistence of the transferred DNA after deposition. Current DNA technology cannot conclusively answer the question of when DNA was deposited on an item or by what mechanism (i.e. direct or indirect transfer). It is possible the DNA detected on M2022-4843 Item 1.1 resulted from secondary transfer; however, based on Nowlin's training and experience it is her opinion given the quantity of DNA detected on M2022-4843 Item 1.1 (0.168ng / µl) and given the DNA profile obtained is single source it is more likely the result of a direct transfer.
State's Exhibit S-11 (Nowlin Rebuttal Discl.).
The State filed an " Amended Supplemental Disclosure " for Ms. Nowlin on March 3, 2025 (" Exhibit S-7 ") but it did not change the foregoing paragraph.
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IV. ANALYSIS
Defendant's argument is three-fold. First, he seeks to exclude any testimony by Ms.
Nowlin regarding when and how the DNA found on the knife sheath was transferred there, arguing it conflicts with the current consensus within the forensic science community, is outside her expertise and is speculative. Second, he argues generally that use of the terms " touch " and " contact " DNA should be prohibited at trial as misleading, confusing and unfairly prejudicial.
Finally, he argues that Ms. Nowlin's rebuttal opinions must be stricken as improper rebuttal.
Each will be addressed in turn.
A. Ms. Nowlin May Offer Disclosed Testimony about DNA Transfer.
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. IRE 702. To determine whether expert testimony is admissible, the district court must consider two factors. State v. Caliz-Bautista, 162 Idaho 833, 835, 405 P.3d 618, 620 (Ct.
App. 2017). First, to give expert opinion testimony, a witness must be qualified as an expert on the matter at hand. Id. Second, once the witness is qualified as an expert, the trial court must determine whether the expert's opinion testimony will assist the trier of fact in understanding the evidence. Id.; IRE 702. Expert opinion which is speculative, conclusory, or unsubstantiated by facts in the record is of no assistance to the jury in rendering its verdict and, therefore, is inadmissible as evidence. Weeks v. E. Idaho Health Servs., 143 Idaho 834, 838, 153 P.3d 1180, 1184 (2007).
1. Ms. Nowlin is sufficiently qualified.
Whether a witness is sufficiently qualified as an expert is a matter largely within the discretion of the trial court. Id. In arguing Ms. Nowlin is not qualified to render an opinion on DNA transfer, Defendant contends that within the forensic community, there is a consensus that only experts specially trained in DNA transfer are qualified to render such an opinion. He asserts that, as a lab analyst, Ms. Nowlin does not have the expertise to proffer an opinion in this case as to how the DNA was transferred to the sheath.
To establish this " consensus, " Defendant relies on two forensic science publications regarding DNA transfer, both of which recommend that DNA analysts should avoid rendering opinions regarding DNA transfer absent specialized training. The first article, authored by five 3
forensic scientists in 2019, discusses " what we know about DNA transfer and the associated elements of DNA persistence, prevalence and recovery, sometimes referred to as DNA-TPPR. ” R. van Oorschot, et. al., DNA transfer in forensic science: A review, Forensic Science
International: Genetics, Volume 38, pp. 140-166 [p. 2] (Jan. 2019).2 The express purpose of the article is to " assist casework investigations of criminal activities " and the information therein " should be used where relevant. " Id., p. 2. It further states:
Appropriately trained forensic practitioners are best placed to provide opinion and guidance on the interpretation of profiles at the activity level. However, those requested to provide expert opinion on DNA-related activity level³ issues are often insufficiently trained to do so. We advocate recognition of DNA activity associated expertise to be distinct from expertise associated with the identification of individuals. This is to be supported by dedicated training, competency testing, authorisation, and regular fit for purpose proficiency testing.
Id.
Notably, the journal in which the article appears-Forensic Science International:
Genetics is an international one and each of the five scientists are from outside the United States. Id., p. 1.
The second article is a report published in May of 2024 by a group of individuals referred to as the " Expert Working Group (EWG) on Human Factors in Forensic DNA. " 4 Melissa Taylor, et al, Forensic DNA Interpretation and Human Factors: Improving the Practice Through a Systems Approach, NIST Interagency / Internal Report – 8503 (May 6, 2024). The express purpose for the report-which was sponsored by the U.S. Department of Commerce's National Institute of Justice Office of Investigative and Forensic Sciences-was to " conduct a scientific assessment of the effects of human factors on forensic DNA interpretation with the goal or 2 Defendant did not provide this article to the Court. The Court obtained a 19-page portion of the article from the web, including the abstract which contained the quote relied upon by Defendant. The web version does not reference the page numbers of the published article (i.e., pp. 140-166), but is paginated as pp. 1-19. The citations herein are to the web version. https://www.sciencedirect.com/science/article/abs/pii/S1872497318303958#preview-section-citedby 3 By " activity level, " the authors mean " the generally accepted hierarchy of propositions for evaluation of evidence in forensic science. " R. van Oorschot, p. 3 4 Available at: https://www.nist.gov/publications/forensic-dna-interpretation-and-human-factors-improving-practicethrough-systems.
There were approximately 25 individuals in the EWG. They included an international group of forensic science experts in DNA interpretation, academics in forensic science and law, statisticians, cognitive scientists, and representatives of professional organizations and standards-developing organizations.
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recommending strategies for improving the production, evaluation, and communication of DNA results. " Taylor, et al., p. 1. Section 7 of the report is dedicated to DNA transfer; specifically, the " how and when " questions. With regard to expert testimony regarding the transfer of DNA, the report explains that " [e] xcept in ground-truth-known experiments, where an individual is observed to have been in contact with a surface / location, it is not possible to know whether the transfer was direct or indirect. " Id., p. 172. It further states that providing opinions about the probability or possibility of direct or indirect transfer is " problematic " stating:
Evaluations considering factors such as transfer, persistence, and background require and evaluation of the biological results given propositions that address not the source of the DNA, but the activities that may have taken place. This in turn requires the use of data, knowledge, and expertise on DNA transfer, persistence, prevalence, and recovery (DNA-TPPR) [] rather than knowledge of DNA profile characteristics, probabilistic genotyping software (PGS), and population frequencies. In this regard, DNA-TPPR, and assessments given activity-level propositions, are a separate skill, distinct from ' standard ' DNA profiling and interpretation []. It may be a function limited to only a portion of DNA analysts with the required expertise. At present, there are not adequate educational opportunities to inform these types of issues within the United States.
Id., pp. 173-74.
The report goes on to note that " [a] n expert rarely (if ever) has all the information needed to perform a robust, balanced, and transparent evaluation of biological results regarding transfer or specific activities on the witness stand. " Id., p. 175. Consequently, the report advanced the following recommendation:
Recommendation 7.1: DNA analysts should not opine about the possibility or probability of direct or indirect transfer having occurred in a case.
Id., p. 177.
Based on these two articles, Defendant posits that Ms. Nowlin, as a " typical lab analyst, " is not qualified to substitute her judgment in the face of the " weight of the forensic community's agreement that the science and literature does not support any analyst testifying about the when and how of transfer. " Mtn., p. 8.
The State responds that Defendant's argument is both legally and factually flawed. The legal flaw is that it misapprehends the appropriate standard to determine admissibility of an expert opinion. The State asserts the standard is not the " consensus of the scientific community " but on whether her knowledge will assist the trier of fact. The factual flaw is Defendant's failure 5
to mention the lack of consensus in the EWG report regarding Recommendation 7.1. Footnote 455 of the article notes that two EWG members dissented from the recommendation, stating:
While [the dissenters] acknowledge that analysts are often asked to respond to ' how ' and ' when ' questions in criminal cases and agree that testimony on this subject can be misleading or otherwise problematic, they believe that the broad prohibition in Recommendation 7.1 puts the proverbial ' cart before the horse ' by not first requiring an assessment of the type outlined in Recommendation 7.3.5 Moreover, they worry that supporting 7.1 would imply the need for analysts to shift to a new paradigm that has not yet been sufficiently vetted within the specific context of the U.S. Court system.
Id., p. 177, n. 455.
The Court finds Ms. Nowlin to be sufficiently qualified to render her opinion on DNA transfer, despite her lack of specialization in DNA-TPPR. The test for determining whether a witness is qualified as an expert under IRE 702 is " not rigid. " Weeks, 143 Idaho at 837, 153 P.3d at 1183. A qualified expert is one who possesses " knowledge, skill, experience, training, or education. " IRE 702. This language " is intended to provide wide latitude in how a witness may qualify as an expert. 6 Clifford S. Fishman & Anne Toomey McKenna, Jones on Evidence § 43: 4 (7th ed.) (Dec. 2024 update). In situations where a witness has " general expertise in a broad subject but is not a specialist in the specific aspect of that subject that is pertinent in the case [,] [m] ost courts conclude that general knowledge can be sufficient to qualify the witness as an expert. " 29 Federal Practice & Procedure (Evid.) (Wright & Miller) § 6264.2 (2d ed.) (June 2024 update). " This is because the issue under Rule 702 is simply whether the testimony of a witness with only a general background is reasonably likely to help the trier of fact, not whether a specialist would be preferable. " Id. " Differences in expertise bear chiefly on the weight to be assigned to the testimony by the trier of fact, not its admissibility. ” Huss v. Gayden, 571 F.3d 442, 455 (5th Cir. 2009).6 According to her affidavit, Ms. Nowlin is " currently qualified and proficiency tested as a DNA analyst " and has been so qualified for twenty years. Aff. Nowlin, ¶ 4. Her C.V. reveals that 5 Recommendation 7.3 acknowledges the lack of DNA-TPPR educational opportunities within the United States and recommends that the federal government " fund collaborative efforts to review the foundations and principles of evaluating biological results when considering alleged activities " and, depending on the findings, makes funds available " to educate and guide DNA and legal communities on the review, research, selection and validation of appropriate methods to account for [DNA-TPPR] when assessing biological results. " Id., p. 182 6 Given at IRE 702 is substantively similar to its federal counterpart, federal authorities interpreting FRE 702 are instructive. Martin v. Hoblit, 133 Idaho 372, 376 n. 3, 987 P.2d 284, 288 n. 3 (1999).
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she worked as a forensic scientist in Biology / DNA at the Idaho State Police Forensic Services Laboratory for eleven years before becoming its Manager. She is certified by the American Board of Criminalistics and is a Molecular Biology Fellow. She is a member of four professional organizations in the forensics field. She has taught courses to law enforcement and medical personnel on DNA in the forensics context and has published scholarly articles on the subject.
Based on her professional experience in the forensic DNA field, Ms. Nowlin-at the very least-possesses the general expertise to opine to matters of DNA transfer. Given her general expertise, any lack of specialized DNA-TPPR training as advocated by Defendant's authorities goes to the weight of her testimony, not its admissibility. Further, in challenging her qualifications, Defendant is seeking to hold Ms. Nowlin to an aspirational standard of expertise in the forensic field that is, for now, is nothing more than a recommendation and a disputed one at that within a segment of the forensic science community. " Not only do Defendant's articles fail to establish any established standard of qualification, Ms. Nowlin disputes that there is a " consensus " in the forensic DNA community that DNA lab analysts should not opine as to DNA-TPPR. Id., 5. She points out that not only were there dissenters to the EWG's Recommendation 7.1, there is " a divide in for forensic DNA community on this topic. " Id., 6.
She explains:
One side supports the [EWG's] recommendation. The other side believes that not offering an opinion based on knowledge of molecular biology / DNA when it may aid the trier of fact is unethical. At the most recent American Academy of Forensic Sciences meeting held in Baltimore in February of 2025, there were presentations supporting both sides of this argument, demonstrating the current divide in the community.
Id.
More importantly, Idaho has not adopted the standard for admissibility set forth in Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993), which considers, inter alia, whether the expert's theory is " commonly agreed upon or generally accepted. " Weeks, 143 Idaho at 838, 153 P.3d at 1184 (noting that the expert's opinion need not be based on information that is " commonly agreed upon " or " universally accepted. "). Therefore, whether there is a general consensus supporting Ms. Nowlin's opinion or not is irrelevant to its admissibility.
" Defendant has not established a scientific consensus in the United States outside of the EWG group, which is comprised on only 25 individuals, only some of which are forensic scientists.
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Notably absent from either party's briefing are court cases discussing the issue of whether DNA analysts are qualified to testify to DNA transfer. A review of case law reveals that such opinions are offered by " DNA experts " without disputes over qualifications. It appears only one court (a military court) has squarely addressed the issue and declined to find the DNA analyst was unqualified to render testimony. United States v. Hill, 63 M.J. 718, 722 (A.F. Ct.
Crim. App. 2006). In doing so, the court rejected the notion that DNA transference was a " separate science ” from DNA extraction and analysis and, therefore, the " expert in DNA ” was qualified to testify to transfer. Id.
In sum, given the liberal standard for qualifying a witness, Ms. Nowlin's experience and training in the area of forensic analysis of DNA generally, the current divide in the forensic community regarding whether lab analysts are qualified to testify to DNA transfer, and the lack of jurisprudence on the matter, the Court declines to find that Ms. Nowlin lacks the qualifications necessary to provide an opinion on DNA transfer in this case. Defendant's challenges to her qualifications affect simply the weight to be afforded her testimony.
2. Ms. Nowlin's testimo