Maureen Maher

And I thought, really, if you believe that my life was being threatened and I'm still a target for whoever didn't succeed in killing me, and now you're highlighting my picture on the news?

But the IRA story and a connection to Jean never checked out.

As the weeks dragged on, it looked like the killer actually might get away with it.

Did you get to that point that you thought we may never know who did this?

Yes, although my heart didn't want to accept it.

I mean, I just felt so strongly that, you know, it would be this terrible, you know, shadow over my mother and my father and my sister and myself.

Meanwhile, Gene Calvados was still holding out for that one perfect tip to come in.

After following a series of false leads, dead ends, and spending about a million dollars, the task force had been shut down.

Then, nearly six months to the day of the murders, two teenagers walked into the Winnetka Police Department with an incredible story and blew the case wide open.

So I called Gene Kilvitas, and I said, Gene, you're not going to believe this, but a kid just came in here and told me he knows who killed the Langers.

Six months after the murders of Nancy and Richard Langer, Winnetka Police Sergeant Patty McConnell was on duty when two teenagers walked into the station asking about the Witness Protection Program.

Do you think they're playing a joke, or do they look afraid?

No, they definitely were not playing a joke.

He was clearly very nervous.

He was Fu Hong, a senior at New Trier High School who walked in with his girlfriend.

David Biro had bragged to his good friend about the killings, but said nothing about his motive.

He said, you know, he's got a gun in his room.

He showed me the gun, and he said he got afraid that he thought he was going to kill again.

Spiro was no stranger to the Winnetka police.

You know, I was very skeptical.