CHESTER, Ill. — Four years ago, the words of Drew Peterson’s missing wife sent him to prison.

Now, the cocky ex-cop’s own big mouth will keep him there.

It took a downstate jury barely an hour Tuesday to find the former Bolingbrook police sergeant guilty of trying to have Will County State’s Attorney James Glasgow killed. Prosecutors said Peterson offered $10,000 to a Satan’s Disciple known as “Beast” to make it happen — but the fellow inmate wore an FBI wire, catching Peterson on tape.

The speedy verdict seemed to doom Peterson, 62, before it was even read. He rested his head in his left hand as jurors sealed his fate, while the sister of Peterson’s still-missing fourth wife sat nearby. Cassandra Cales later told reporters it was worth the long drive to the courthouse 350 miles southwest of Chicago to see Peterson convicted all over again.

And she said, “Karma’s catching up with him.”

“He’s going to stay in prison forever,” Cales said.

Peterson might have never seen a prison cell had Cales’ sister, Stacy, not vanished in 2007. That set in motion the events that led to Peterson’s 2012 conviction for the murder of his third wife, Kathleen Savio — and the 38-year sentence he has been serving at Menard Correctional Center since 2013.

Peterson has never been charged in connection with Stacy’s disappearance, but Glasgow said after Tuesday’s verdict that, “we never stop reviewing that case.” He led the team of prosecutors that secured Peterson’s first conviction, and comments Stacy made to two men before her disappearance were crucial in that case.

The Illinois Supreme Court has agreed to hear Peterson’s appeal in the Savio murder. But his latest conviction carries a minimum 20-year prison sentence. Authorities say the clock won’t start ticking on the new sentence until Peterson is done serving time for Savio’s death. And that means Peterson won’t be getting out of prison any time soon.

A sentencing hearing has been set for July 26. Randolph County State’s Attorney Jeremy Walker said he will seek a sentence near the maximum of 60 years.

Peterson’s latest trial in the downstate city of Chester lasted roughly a week. During Tuesday’s closing arguments, Walker pointed his finger at Peterson like a dagger and told jurors to “find this man guilty.”

“A prosecutor deserves to go home at night and not worry about getting shot in the head,” Walker said.

Peterson leaned back in his chair and crossed his legs at times, listening to lawyers spend two hours summarizing the case for the jury. Peterson enlisted Antonio Smith — the Satan’s Disciple called “Beast” — to help pull off Glasgow’s murder. Smith, a 25-year-old inmate serving 40 years for crimes that include attempted murder, wore a wire on Peterson late in 2014.

During a Nov. 13, 2014, recording, Smith questioned Peterson about his hope to get out of prison, “with Glasgow gone, right?”

Peterson said, “Yes, it’ll get me out.” Smith asked if “it’s a go, a 100 percent?” And Peterson replied, “it’s better.”

“Because what he’s doing is, he’s f—— beating me under the table,” Peterson said. “He’s calling these judges or going golfing with them or some f—— thing. So with that happening, how, how can you fight that?”

Walker said Peterson was driven to have Glasgow killed for four reasons: Peterson wanted to protect his pension; he wanted to win his appeal; he didn’t want to be charged with the murder of Stacy Peterson; and he was mad that his son lost his job at the Oak Brook police department.

Assistant Attorney General Steve Nate acknowledged he played so many recordings from Smith’s wire during the trial that jurors probably wanted to “throttle” him. But Nate said Peterson and his attorney “can’t get around the recordings, ladies and gentlemen. They can’t get around his own words.”

“He said it, he meant it, and he’s guilty,” Nate said.

Peterson attorney Lucas Liefer mocked the case. He said it was “muddied” by the involvement of Glasgow’s office. And he started his closing argument by telling jurors he could be Randolph County’s state’s attorney — if only Walker weren’t around.

“Oh my gosh, did I just commit solicitation of murder?” Liefer asked facetiously.

Liefer later told jurors they never explicitly heard Peterson ask Smith on tape to have Glasgow killed.

“How has the state met their burden of proof on a crime of words when the key words — ‘murder’ or ‘kill’ — are never spoken by the defendant?” Liefer said.

But while Peterson said on the tapes that Glasgow would “never leave me alone,” Nate said the obsession was really Peterson’s.

“It’s the defendant who’s obsessed with James Glasgow,” Nate said. “Not the other way around.”