ORLANDO, Fla. – University of Central Florida forensic scientist Dr. Candace Bridge has created a first-of-its-kind database for when DNA fails to identify a suspect in a sexual assault case.
Bridge, working in UCF's National Center for Forensic Science laboratory, has analyzed and cataloged 112 lubricants used primarily for sex.
They are all unique enough, Bridge said, that they could help link a suspect to a crime scene.
"When we analyze the lubricant, then we can say, 'Oh, this is a flavored, water-based lubricant that has a polyethylene glycol base or a polybutylene glycol base,'" Bridge said. "In the absence of DNA, such as if a condom is used or a spermicidal lubricant, or anything that would kill DNA sources, we're hoping that using the lubricant from the condom could create a link between the victim and the suspect."
Bridge, who graduated from UCF in 2007, said the process is similar to paint chips identifying the make and/or model of a car that left the scene of a hit-and-run crash. Just like paint chips can't identify the driver, lubricants can't convict a suspect. But they can point police in the right direction.
"And then they can start looking for people that possess that type of lubricant, as well as people that possess that lubricant and know the victim or have a reason to be around the victim," Bridge said. "And so, if we can provide one more link or one more tool to the tool belt for the detectives and the police investigators to use, that's what my goal is."
Bridge first began studying lubricants as a forensic chemist and research physical scientist with the U.S. Army's Defense Forensic Science Center. She has continued her research at UCF during the past five years.
She discovered DNA was not solving an alarmingly high number of rape cases because DNA wasn't left behind by the suspect or the suspect's DNA was not in law enforcement's database.
"There are different scenarios when it comes to sexual assaults," Bridge explained. "You have the unknown predator, and a lot of times if they are a serial rapist, they will bring condoms because what they're trying to do is limit the number of people that they can connect based on their DNA because the protocol is always: you analyze your unknown sample, you analyze your known sample, and you analyze a reference sample."
She said rape victims lose hope that they will ever see justice and some are embarrassed or afraid to report the crime.
"I think many victims are afraid that if there's no DNA, they're not gonna catch the person," Bridge said. "And so I'm hoping that we can give them confidence that we're trying to find other ways to connect the victim to the suspect or the suspect to the crime scene at least, in order to provide some more justice."
Bridge calls her database the SAL - Sexual Assault Lubricant database.
She is making it free and available to law enforcement anywhere in the world. She is also developing a protocol for other researchers to add to the database.
Bridge just received another $354,000 grant from the National Institute of Justice to continue her research.