We've been watching this case out of Moscow, Idaho, home of Idaho State, where four students were stabbed and murdered.

We, maybe even in their sleep, back in November.

We didn't know a whole lot about what was going on with the case, but the police and the FBI were on it, and they were making breakthroughs along the way.

Joining us to tell us about those

breakthroughs and how they did it is our ABC News correspondent, Alex Stone. Alex, always good to talk to you,

my friend, and Happy New Year. What's the latest here out of this case that went from Idaho to Pennsylvania?

Yeah, hey, Chris, happy New Year to you as well. And you remember for so many weeks now, and we've talked about it with John and Ken,

and it was what is going on, that it didn't seem like police really were going anywhere in this.

And family members of the victims, they were worried that it was going cold.

And by many accounts, it was somewhat that they didn't have a lot of leads, but they got a DNA match

and they were able to work that.

And in the last week, all of this broke open and they were able to make the arrest on Friday.

And what we know, and a couple of things that we've been learning today, so not only was it DNA,

but they used public genealogy databases to find him. So this is one of those where it seems at the moment, according to law enforcement sources,

that they had a piece of DNA that maybe a week, two weeks ago, they got a hit back on from the

lab, but they didn't know who would belong to, there was somebody unknown there, and they

went to those public genealogy databases that we know more and more about that investigators

have been using and either found Brian Coburger, the 28-year-old accused killer

now, or a family member, and then they worked it from the family member. They knew somebody was

related and then said, well, this somebody lives very nearby, and then worked it from there,

and this somebody has a white alontra that they had been looking for for many weeks, and then worked it from there and this somebody has a white a launtra that they had

been looking for for many weeks and then they were able to make the arrest and the police chief

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