The I-Team has followed the case for decades.
I-Team original coverage of David Chereck murder
"To know that he can't hurt another boy ever again lightens my heart," she said.
Esther Chereck said when she testified during the trial, Serritella refused to make eye contact with her. But she says with this guilty verdict, he can look away no more.
Full interview with 1992 murder victim David Chereck's mother
It took 27 years for Serritella to answer for the murder of Esther's only child.
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"I just like almost fell on the floor. I just kind of rolled forward, and my cousin grabbed me, and you could hear the silent cheers," Esther said.
David Chereck, 15, of Skokie was last seen on New Year's Day in 1992 after a night at a bowling alley with friends. His body was found in a Morton Grove Forest Preserve. He had been strangled with a scarf.
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Suspicion centered on Serritella; he'd come forward as a witness but then disappeared, only to be found by the I-Team's Chuck Goudie in Las Vegas in 1998.
"I looked in my rear view mirror, and there was another white car just similar to mine that this boy jumped into, and as they jumped in, I took off, and they took off, and they passed me," Serritella told Goudie in 1998.
"I thought that he was so guilty, but also so guilty in his soul," Esther said.
Still it took 16 years and the formation of a cold case team for Serritella to be arrested. His defense said there was no physical evidence or witnesses, but his own words did him in. His interview with Chuck Goudie was part of the prosecution's case, as well as testimony from cellmates who said he talked about the murder.
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For Esther, justice delayed is still justice, but not closure.
"People say it'll bring you closure. It's no such thing. When you've lost a child, the only closure is when you die and your souls touch again. That's closure," she said.
The 76-year-old Serritella faces a sentence of 20 to 60 years. Esther Chereck says she set Serritella aside emotionally years ago. Yesterday's verdict, she says, was for David.