A study by the NIJ revealed that out of 2,000 sexual assault kits, 660 of them—or 33 percent—had no usable DNA to test. So, what happens to those 660 victims? An investigator has to tell them there’s nothing the police can do about possibly the most traumatic experience of their life and the case is now considered closed.
There may not be DNA evidence, but what if there is other evidence in the kit that could be used to narrow down the suspect pool, associate a suspect to a scene or victim and even provide investigative leads? Right now, that other evidence is not generally considered—something Candice Bridge and her team at the National Center for Forensic Science is trying to change.
Bridge is the founder of the Sexual Lubricant Database, a compilation of reference lubricants, characterization data, instrumental data and classification models that can assist forensic scientists in conducting lubricant analysis in sexual assault cases. The database includes detailed information about nearly 120 commercially available sexual lubricants and person hygiene products.
Historically, the analysis of lubricants has been based on the presence of PDMS, PEG and/or cornstarch particles in the event a condom was used. But in a lightbulb moment, Bridge realized there is a lot more information than just those elements that can differentiate lubricant samples, such as flavor, fragrance or anesthetics.
“The primary goal of the database is to provide the community with a resource for analyzing sexual lubricants in sexual assault cases,” Bridge told Forensic. “When analyzing unknown samples, the community can look back at something in this reference database and say ‘hey this looks really similar.’ They can go to the investigator on the case and say, ‘if you find anything at the crime scene that smells like raspberry, we can associate it with this specific lubricant.’”
Bridge says the interest in forensic lubricants is greater outside of the United States than inside since the U.S. puts more weight on DNA than other countries. So, in addition to the database, Bridge and her team have put together a forensic working group and a survey to better understand current processes and procedures, if any, for lubricant analysis.
The mission of the Forensic Working Group for Forensic Lubricant Analysis (FWGLube) is the promotion and advancement of forensic lubricant analysis for operational use. Their goals include:
- Promote the inclusion of forensic lubricant analysis in operational forensic laboratories
- Validate the Sexual Lubricant Database
- Determine the evidentiary strength of lubricant bases (i.e. PDMS, PEG, etc.) in sexual assault cases
- Develop standard analytical protocols for lubricant analysis
“Developing resources, methods, protocols, extraction processes and considerations that should be determined when incorporating forensic lubricant analysis is why I started the database in the first place and developed this working group,” Bridge said.
Danielle Green, a Ph.D. candidate in Bridge’s lab at the University of Central Florida in the National Center for Forensic Science, has been at the forefront of the sexual lubricant survey. Green said she and her colleagues have a lot of anecdotal evidence that the need for sexual lubricant trace analysis is growing, but now is the time to get it down on paper.
“We want to collect data from different laboratories and law enforcement organizations to understand the needs and gaps that are present for sexual lubricant analysis in crime labs,” Green said. “What we don’t know right now is the reason for some of the roadblocks. Is it information- or knowledge-based, is it instrument-based, is it a lack of time? Do examiners have time to validate an entire protocol, or do they just not see the value in this particular information? If that’s the case, why?”
Beyond understanding the needs of the forensic lubricant community, the results of the survey could help Bridge, Green and the rest of the lab demonstrate the value of forensic lubricant analysis to accreditation organizations like the American Academy of Forensic Sciences (AAFS).
“If we can demonstrate there is a lot of people interested in forensic lubricant analysis, we may be able to find more agencies to fund it,” Green said. “The survey creates a snapshot we can take to these meetings and say, ‘this is a valid need crime labs big and small have requested, and we need to put time and effort into this.’”
Cold case implications
DNA analysis and genetic genealogy have revolutionized the investigation of cold cases throughout the world. Could forensic lubricant analysis do the same for the hundreds of thousands of rape kits from years ago that still sit in a police storage closet somewhere?
“I honestly don’t know,” Bridge said. “But it’s an educated I don’t know because of the simple fact that storage for DNA is different than storage for lubricants.”
DNA needs to be dried out and stored in a freezer to preserve future evidence for analysis. For lubricants, it is critical that the evidence be placed into a sealed container. Otherwise, all of the volatile information that would provide researchers with differentiating characteristics would evaporate almost immediately. So, in the world of cold cases, unless a forensic lab technician initially recognized a lubricant sample, put it into solution and preserved it correctly, the data may just not be there.
Still, Green and lab members Santana Thomas and Brooke Baumgarten are working to understand the long-term effects environmental and storage influences can have on lubricant samples to both better assist on cold cases and be able to provide information to forensic labs when it comes to storage for these special samples.
If one was to extrapolate in all positives, Bridge and her laboratory could get the process, methodology, protocols, etc., accredited by a forensic agency and implemented into crime scene and crime lab analysis. Then, investigators would collect, analyze and preserve lubricant samples in a way that would allow them to be analyzed now and in the future—much the same way investigators 30 years ago preserved DNA evidence until a time when we had the necessary technical wherewithal.
“Nothing in forensics is the end-all-be-all. It’s all a part of a puzzle. It’s about individual pieces that will tell the whole picture. Our goal in developing this area of forensics is to add another piece that American crime labs can consider when going to a crime scene or analyzing sexual assault kits. It’s another tool in the toolbox that should be available,” Bridge said.
If interested, you can access the survey here. It should take 5 to 10 minutes.
Photo: Candice Bridge working with DART-MS in her laboratory. Bridge earned her Ph.D. at the age of 25 and was one of the first people with a forensic Ph.D. in the country. She was also the first Black female to teach chemistry at Howard University and the University of Central Florida. Credit: Candice Bridge