VALDOSTA, Ga. – Companies like 23andMe and AncestryDNA help people trace their family's history.
John Hogan took one of those DNA tests and sent it off to learn more about his relatives. He had no idea Orlando homicide detectives also got his genealogy information.
"When you told me that my DNA helped solve a 17-year cold case murder, I just couldn't believe it," Hogan said.
Hogan had never heard of Christine Franke, a 25-year-old University of Central Florida student who was gunned down in her Orlando apartment in 2001.
Police said the killer left his DNA behind at the crime scene. But for 17 years, detectives could not match that DNA to anyone.
"I was always interested in my heritage and my family and my culture," Hogan said.
A few years ago, Hogan signed up for the genealogy service AncestryDNA. His DNA test results were later uploaded to GEDmatch, a separate online database used to identify potential relatives.
"We have a huge, huge family," Hogan said.
Little did Hogan know, Orlando police had uploaded the killer's DNA information to that same database. Detectives soon discovered that the person who allegedly murdered Franke was genetically related to Hogan.
Starting with Hogan, genealogists identified his parents, grandparents and great-grandparents, including Charlie Burgman, who died 50 years ago and is now buried outside a rural church.
Investigators then began tracing Burgman's other descendants. It led to two brothers in Orlando.
Undercover detectives secretly collected a Gatorade bottle used by Reginal Holmes but determined the DNA he left on it was not a match. So investigators turned to his brother, whom they saw smoking cigars.
Police say DNA on the cigar tips matched DNA at the crime scene.
Soon, Benjamin Holmes was in handcuffs.
"If you break the law, and you commit a crime -- in this case, it's a murder -- you have to stand trial, and you have to go to jail," Hogan said. "You have to pay the penalty."
Hogan said he did not feel his privacy was violated, but others have raised concerns. Just months ago, that genealogy database, GEDmatch, changed its rules. You must now opt in to allow police to use your information. But authorities can still obtain a warrant to get it.
Benjamin Holmes has pleaded not guilty. His attorney said they will be challenging the way law enforcement used the genealogy database.