Sexual Assault Medical Forensic Examination Research Forum: Evolving DNA Technology

On this page find summarized discussion on:

Collection of DNA

Patricia Speck presented on this topic. Questions raised included —

  • What is the impact of the medical forensic history on gathering DNA evidence? Several participants mentioned that it can improve documentation of offender characteristics and provide direction for evidence collection.
  • What training do examiners receive to guide their decision on whether to collect DNA evidence?
  • What training do examiners receive regarding methods of DNA collection? From the lab perspective, how should examiners collect blood samples for DNA testing specifically? Is there evidence to create a consistent method for DNA collection given a type of assault?
  • What training and information is disseminated to law enforcement and examiners about the scope and limitations of DNA evidence insofar as what it tells us (about infertile or vasectomized males, about identity but not consent, etc.)?
  • Where and under what circumstances should touch DNA be collected? Who collects touch DNA samples will likely vary. For example, one participant noted that if an offender may have touched a pen at the crime scene, law enforcement will likely collect it. If it is potentially on the victim’s skin, examiners should swab the areas touched. What training do examiners, law enforcement, and prosecution receive around touch DNA? (One participant noted that his local crime lab has done studies showing some low-level profiles and a few single ID profiles from specimens collected as touch DNA, but the chance of getting a profile is remote and sometimes works against a case if the profile is so low that the contribution of the defendant can not be determined.)
  • What is the future of DNA collection in terms of specimens (saliva, urine, blood, etc.), methods, and timeframes for collection? What could the impact be on victims, lab processes and findings, case outcomes, and costs? What is the economic impact of extending time for DNA collection? A cost-benefit analysis might be useful.

Body Fluid vs. DNA

  • How do labs decide what samples to test first? Does the medical forensic history affect this decision?
  • How important is identification of bodily fluid for prosecution purposes? Does screening for bodily fluid have to be done? What are the costs, time, and workforce implications for the crime lab of going straight to DNA analysis (e.g., Y-STRs)? Several participants noted it would save both money and staff time. Even though serology is less costly, going straight to DNA analysis saves 30 to 60 days of waiting for serology testing results. What is the benefit/cost of going straight to DNA analysis and not doing serology testing on the court outcomes? It was noted that NIJ-funded research is being done in Detroit and Houston on this question. It may be possible to get DNA first and then go back later to do a bodily fluid analysis if needed.
  • What are labs asking for in their kits regarding DNA and bodily fluids? Why are some labs better at finding forensic results?

A further question is: How often is the lack of kit findings that speak to these weak links in a case a crutch for investigators and prosecutors not to take a case? To get feedback on this question, it may be useful to survey law enforcement and prosecutors using vignettes and ask them how they would proceed given case circumstances and kit findings. How can training for prosecutors, law enforcement, examiners, and advocates make a difference in whether cases with these perceived weaknesses go forward? What additional evidence can be collected through the SAMFE to corroborate a victim’s account in cases where consent is contested or there was drug-facilitated or incapacitated sexual assault?

Kit Backlogs

  • Why are kits left untested? Are some kits left untested because they are cases the criminal justice system doesn’t want to pursue (when victims have used alcohol or drugs, work in the sex trade, or gave consent is the question)? To what extent does kit evidence matter in non-stranger cases? Offenders often follow a serial pattern, assaulting both strangers and acquaintances, thereby potentially linking evidence to both a stranger case and an acquaintance case.
  • What are reasons for collecting DNA samples in consent cases? For example, if the defense is consent, the prosecutor wants the kit analyzed by a lab in order to suggest how careful everyone was with the evidence, from the examiner to crime lab. It may not add anything initially, but it is important in cases where there are consent issues to be able to say all the evidence affirms the victim and lends credibility to the case.
  • What is the real impact of DNA on cases? What is the real importance of creating a database on offender DNA? Researchers need to better understand the concept of forensic hits and usefulness of DNA in consent-only cases. Participants noted an Arizona State University study that looked at prosecution and the decisionmaking process in Los Angeles County, California. Findings indicated that the lack of good evidence predicted whether the district attorney took or dropped a case. On the other hand, the perceived risk-taking behavior of victims was associated with the likelihood of the case being dropped. It would be helpful to gather similar information about case outcomes in other parts of the country.

DNA Preservation Questions

Cecilia Doyle presented on this topic. It appears that there were answers to some of the questions raised at the forum related to DNA preservation — for example, what samples need refrigeration and how quickly refrigeration is required — but there is a gap in consistently getting accurate information to examiners and law enforcement. What are crime labs across jurisdictions instructing examiners and law enforcement to do with regard to preserving evidence? Why are labs giving different information? What are the resources in the lab to preserve evidence? A broad-based survey of crime labs might be useful to gather baseline data.

  • As new devices/techniques are available to collect DNA (e.g., nylon swabs), are they more resistant to harsh conditions? What if DNA samples are collected in areas where it may take longer to get samples to refrigeration or they are subjected to higher levels of moisture and heat?
  • How quickly is refrigeration of urine or blood samples necessary? For example, are 6 hours in a locked file at room temperature okay or would these samples need refrigeration sooner?
  • Is there research that can help providers who have to make decisions about how to best preserve liquid samples? Several participants indicated the answer is yes. For example, numerous studies of GHB in urine samples indicate the drug breaks down at a fast rate, so it is important to refrigerate it as soon as possible. Studies of body fluids and DNA have been done that show heat and moisture will break down the samples. If they can be cooled, that is the best option, but if drying a sample, put it in a cool environment to dry and then send it to the lab. One participant noted that limited research suggests that adding a certain type of preservative to blood samples might be helpful in preservation.
  • Are dried samples still best for DNA evidence and on what type of swab?
  • Is active or passive drying best practice? Active drying should not be done using heat. Passive drying is best depending on how wet the item is and how fast it can be moved to the next step. Do not introduce a breeze across it for drying. Protect evidence from contamination. Air should go through a filter.
  • What if patient has vomited on her/his shirt? Do not air dry in open space; instead, air dry under paper, under air movement, to protect from people talking, walking by. Put it in a room no one is going to be around to protect it from extraneous DNA. Is there a drying closet designated for large items?

Information Sharing

  • What information/findings are crime labs sharing? Participants indicated that labs can only share with their clients, which are law enforcement agencies and prosecutors. [1]
  • What is the process for ensuring the SART, including the crime lab, is collaborative and communicating on cases? What do we need to put a feedback loop in place? Who can make that happen? It would be useful to learn if there are jurisdictions that have such a feedback loop and how it works. One participant noted that in her system, it was the advocate who coordinated the feedback loop.
  • How can we help communities in tracking kitswhere they go (what percentage sit in a closet), if they get analyzed, if they yield probative evidence, their impact on the case, etc.?

Retention and Storage

  • What are the practices across states? The conversation focused broadly on the kit rather than just DNA evidence. It appears that there is much variation in practices across states, particularly in the length of time the kits are stored in reported and unreported cases and where the kits are stored. It would be useful to find out specifically what the practices are and the rationales for the variations. Two studies were discussed that begin to provide this baseline data:
    • Janine Zweig, of the Urban Institute, presented data she and her colleagues collected on kit storage practices across states as part of an NIJ-funded study of payment practices related to the SAMFE. Sexual assault coalitions and state STOP administrators were invited to be part of a survey.
      • While coalitions and STOP administrators tended to know if kits in reported cases were stored (majority were stored), they often did not know how long they were stored.
      • For those who did know, the timeframes they reported ranged from 1 month to 50 years, as well as indefinite storage time.
      • In the case of unreported cases, about a quarter of coalitions and STOP administrators did not know if the state stored the kit. For those who did know, the timeframes they reported ranged from 1 month to 30 years, as well as indefinite storage time.
      • Storage models for non-reporting victims included —
      • No law enforcement involvement, with medical facilities performing the exam and securely storing the evidence (43 percent);
      • Law enforcement storage only, with medical facilities performing the exam and transferring the evidence to a local, county, or state law enforcement agency (62 percent);
      • Anonymous/blind reporting, with information provided to law enforcement without identifying information about the victim or perpetrator, and if the victim has an exam, law enforcement stores any evidence that is provided (36 percent); and
      • Other (16 percent).
    • There were efforts in California to gather data on what happens in the case of anonymous examinations. Questions include: How many exams are done? What percentage of those who have anonymous exams later convert to reporting? What is the time frame between the sexual assault, the exam, and conversion? How many of the converted cases are referred to the prosecutor’s office? What is the criminal justice outcome? Why do cases fall out? Why do law enforcement and/or prosecutors not pursue a case? What about victims who choose never to convert? What was involved in their decision? This research could be replicated across jurisdictions, different underserved groups, refugees, correctional systems, etc.

Storage period for non-reporting/anonymous kits

  • How many rape kits are collected annually and how many are non-reporting? How many of those non-reporting/anonymous cases “convert” to reporting and/or are prosecutable?
  • Is there research or guidance about how long non-reporting/anonymous kits should be kept? For jurisdictions with a short window for holding the anonymous kits, is there a storage issue? A resource issue? Should there be a centralized state holding system for non-reporting kits so that the window can be widened?
  • Why do states have such different procedures for storage of anonymous kits? Which challenges are really barriers and which can be removed? One example of storage practices comes from West Virginia. Anonymous kits are stored at a state university lab (Marshall University Forensic Science Center) for at least 18 months (but are currently being stored indefinitely). In the 4 years this procedure has been used in West Virginia, 52 non-reported case/kits have been stored and 3 converted to reporting. In two of the three cases, law enforcement did not investigate. The one that did move forward was not prosecuted for lack of evidence. What would be the impact (cost-benefit, victim satisfaction, etc.) if all states had a tracking system like West Virginia? Is it feasible for a state crime lab to work with another lab (e.g., a university lab) to do quality assurance on samples and upload that information to a data base for analysis/case tracking?
  • Are jurisdictions processing kits from non-reporting victims? If so, are they uploading DNA profiles into the state database? (Access to CODIS is limited to situations where there is a direct link to a crime, which would require a report.) Participants warned that this was a slippery slope — if the victim chooses not to report, then giving data to the criminal justice system is problematic. The Office on Violence Against Women advises not to process the kit if the victim is not reporting. To process a kit in such instances removes the victim from the center of care because it is taking the choices about the kit out of the hands of the victim.


[1]A related question arose during a review of an early draft of this report: Why does this barrier in information sharing exist when many SAFE programs, which send the evidence to the lab, are currently receiving the results to add to the medical forensic record?

Date Created: September 6, 2012