Transcript for Police find link between Markel’s alleged killers and ex-wife’s family: Part 6
in broad daylight. And so everybody's screaming for some sort of resolve right away. This is a case where for 2 1/2 years we have only seen tidbits of the investigation and now someone is being charged with it. We have arrested sigfredo Garcia for the murder of professor Daniel Markel. So in may, 2016, sigfredo Garcia is the first person arrested in connection with Dan Markel's murder. We have a picture of Mr. Garcia. Sigfredo Garcia, whose friends call him by the nickname "Tuto," has some history with breaking the law. In fact, he's got 22 arrests going back to when he was a teenager. There's a lot of speculation a coincidence or two but nothing that is going to put my client in Tallahassee with a gun responsible for this murder. Garcia is planning to plead not guilty. Now, remember, authorities say when sigfredo Garcia is driving up to Tallahassee, in that car with him is his old childhood buddy, Luis Rivera. Luis Rivera has also been charged with Dan Markel's murder. Now, Rivera was a drug dealer and the leader of the local Latin kings gang. At the moment of sigfredo's arrest, Luis Rivera is already behind bars, in a federal prison outside Orlando. He'd been picked up in a big federal raid against the Latin kings a year bore. The arrests definitely set a new chapter. It switches from the death and the grief and the sorrow and the sadness and now you can go towards looking at some hope in the sense that maybe there'll be some answers. I mean, who are these people? What's their relationship to Danny? The people who end up being arrested for this murder had never met Dan Markel before. They've got no motive. Investigators are in a quandary. Here they have these two pretty low-level criminals from south Florida driving nearly 500 miles Noth to Tallahassee to murder this celebrated law professor they have never met and seem to have no connection with. There's only one conclusion they can draw. If sigfredo Garcia and Luis Rivera don't have any link to Dan Markel and didn't know him they must have been hired by someone who did. There's been a really active investigation. And the cops have been piecing everything together. If it is a murder for hire, police have to look into anyone who might have had trouble with Dan Markel. Don't forget, there was that bitter custody battle between Dan and Wendi over the custody of their two kids, leaving very bad blood between Dan and Wendi's very prominent, very wealthy family. I mean, these children were so adored, and the fighting over them was so extreme, that while it might sound not realistic to think that you would kill over custody, you can see that it would be a powerful enough motive. I don't have evidence to charge the adelsons. I can't go on TV and accuse them of murder without that evidence. But what I can say is, there is a link to that family between our killers. And that link is Katherine magbanua. Katie is a filipino immigrant. She did work in some clubs. She was a bottle girl. But she used her head too. She worked in medical offices and she was somewhat together. This new character, Katie magbanua, enters the fray. And sure enough, she knows both parties in this very sordid soap opera. She had children with sigfredo Garcia, the accused hitman in this case. And not only does Katie have two children by one of the accused hitmen, investigators discover that she knows, guess who, the adelsons. She was receiving regular payments from their thriving cosmetic dentistry practice. And that is how they end up putting together this chain of murder. But can they prove it? You know the expression, "Follow the money"? That's exactly what investigators do here. In the months after the murder, Katie starts getting a regular paycheck every two weeks from the Adelson institute, signed by Donna. But for doing what? There was almost no paperwork for Katie. No work schedule, no application, no record of a job title among the files investigators subpoenaed from the Adelson institute. She was collecting checks from the dentistry. It was not necessarily clear what she was doing for her payment there, but they were able to tie some of these payments from the adelsons to Katie. And when investigators look at Katie's bank accounts, they say they discovered a curious spike in cash deposits. In the year leading up to Dan Markel's death, Katie's deposits totaled about $15,000, but in the year after his murder, Katie's deposits almost tripled. To $41,000. Katie is under surveillance. She doesn't know that her phone is being tapped, but it is. And police are listening to her calls. Including one call she makes to sigredo's attorney. I got to tell you, Katie, it's on the internet and stuff and there's already stories about your involvement in the Tallahassee Democrat, okay? Okay. So my name is out there already? Yes, your name is out there now. Okay? That's already public record? The only reason they would be approaching you now is to arrest you. Okay. So now there's this clear link between Katie and the adelsons. And as investors gather even more evidence, they uncover this photo of Katie and Wendi looking like bffs on the beach in
This transcript has been automatically generated and may not be 100% accurate.