A person who knows about the investigation into the student murders in Idaho says that it took genetic genealogists only a few days to figure out that Bryan Kohberger was the suspect.

One expert says that genealogy has never been used in a real-time, ongoing investigation to lead police to a suspect. Genealogy is often used to solve cold cases like the Golden State Killer, but it has never been used to find a suspect.

The source tells WPBF 25 News Investigative Reporter Terri Parker that the genealogy part of the investigation went very quickly, but that collecting DNA at the chaotic crime scene was a very hard thing for the police to do first.

Four college students were found dead in their beds in a house in Moscow, Idaho. Kaylee Goncalves, Ethan Chapin, Xana Kernodle, and Madison Mogen were all stabbed to death.

John MacVeigh, a former FBI agent, said that it’s likely that crime scene investigators had to first separate the DNA of the victims and other people from that of the killer, which was a huge job.

“They will have to look at it and look at every droplet and other things like that. Because if the suspect cut himself, he wasn’t bleeding as much as they were. So there could be one droplet somewhere, and if you look around a room and see droplets everywhere, you test each and every one of them “MacVeigh said.

The police looked for the unknown DNA in the national CODIS DNA database, but they didn’t find it because Kohberger had never been convicted of a crime.

Sources say that the police then had genetic genealogists upload the samples to a public database like Family Tree DNA to look for relatives who matched.

Genealogists then used birth and death records, census records, and other clues to put together a family tree that went back many generations.

At that point, they move downward from great, great-parents to living people looking to see who is the right age, lives in the area, and could be a possible suspect.

Sources said that Kohberger was the only person left on the list of possible suspects, and police found that he drove a white Elantra like the one they saw near the crime scene.

The FBI started following him after that, and they say they found a piece of trash with Kohberger’s DNA on it that they can definitely match to the crime scene.

That’s the best proof they have, and the genealogy is just the amazing tool that helped them get there.