ORANGE COUNTY, Fla. – Using DNA to catch criminals works only if detectives can match a DNA sample from a crime scene to a person.
The FBI's Combined DNA Index System, or CODIS, stores DNA profiles of convicted criminals and profiles collected from violent crime scenes.
Law enforcement agencies around Florida send their DNA samples collected from crime scenes to the Florida Department of Law Enforcement's lab to extract DNA profiles. The profiles are then compared to existing profiles in CODIS, looking for a match.
If there is no match and no other leads, often the case goes cold.
But now, a technique known as genetic genealogy --- using genetic information to identify likely family members with similar DNA -- is solving cold cases that were considered previously unsolvable, said FDLE Special Agent in Charge Danny Banks.
"Our opportunity here is one of the biggest opportunities we've seen in criminal investigations in many years," Banks said. "And I can count on one hand the number of times I've seen such a great investigative tool give us the opportunity to solve crimes. We're talking about the worst crimes that have been on our files for many many years."
Genetic genealogy points detectives in the right direction, sometimes a new direction, Banks said, generating new leads in old cases.
Last week, the Orlando Police Department and the FDLE announced the arrest of Benjamin Holmes in the murder of Christine Franke in her Audubon Park apartment in 2001.
Detectives said 17-year-old DNA was found at the crime scene but didn't match with any DNA profiles stored in the database.
FDLE's full-time genetic genealogy investigative unit -- the only one in the country, according to Banks -- turned to geneticists at Parabon Nanolabs.
Banks said Parabon Nanolabs first began analyzing DNA to identify fallen service members.
FDLE's two-person genetic genealogy team sent Parabon the DNA profile from a sample collected at Franke's apartment in 2001.
Parabon compared the profile with genetic profiles stored in a public DNA profile database in South Florida called GEDMatch.
GEDMatch exists for people searching for long-lost relatives to voluntarily upload their DNA profile to search for profiles with similar matches, perhaps indicating a relation, according to Banks.
GEDMatch returned a list of the closest DNA matches from the millions of people who have voluntarily submitted their DNA to GEDMatch.
The FDLE team believed the names on the top of the list, based on strong DNA similarities, were likely relatives of the killer who left his DNA behind at Franke's apartment.
From there they created a family tree identifying parents, grandparents, siblings, cousins and even great -grandparents.
Through thorough investigating and interviews, along with cross-checking alibis, ages and criminal histories the team was able to narrow down the family tree.
Eventually, the team obtained a DNA sample from Holmes and found that it matched with almost exact certainty the sample collected from Franke's apartment.
"Genetic genealogy is putting people in jail who need to be in jail for a tremendously violent crime they committed years ago," Banks said. "This type of opportunity is going to help us get results. and it's going to help the families of those victims get some closure."
Banks said his team came to him with the idea of using genetic genealogy to catch criminals after they used the science to find long-lost relatives in their own lives.
"We decided to take ownership of this, we're going to dedicate full-time resources," Banks said. "We got full-time resources committed to using this tool helping those local agencies solve their case. Nobody else is doing this and I'm glad to take that leadership."
Banks said his genetic genealogy team is currently using the science to help solve two cold cases and is close to arresting two more killers.