Former NU professor denies stabbing boyfriend, says British man committed murder during meth-fueled threesome

A former Northwestern University professor accused of brutally stabbing his boyfriend to death denied he committed the 2017 murder Tuesday, saying the deadly attack was solely carried out by another man during a meth-fueled threesome gone awry.

As Wyndham Lathem and Trenton Cornell-Duranleau engaged in an impromptu ménage à trois with Andrew Warren — a British man who flew into Chicago just days before — Cornell-Duranleau, 26, suddenly froze, Lathem told Cook County jurors.

“I felt the bed sag like someone was getting on the bed ... and a second later, he [Cornell-Duranleau] starts screaming,” Lathem, 47, testified through tears. “He’s screaming in my ear.

“I didn’t know what was happening. I didn’t know what Andy was doing to him.”

When Lathem was able to get out from under Cornell-Duranleau, he said he ran to the bathroom of his River North condo.

“I didn’t help him.” Lathem said of his action’s that summer night. “I just stayed in the bathroom while he was being killed.”

Andrew Warren, 61, has pleaded guilty to Cornell-Duranleau’s murder, and testified against Lathem last week.

Warren said killing Cornell-Duranleau while he slept was Lathem’s idea after the older men’s suicide pact fell through.

Lathem first stabbed Cornell-Duranleau, Warren said, admitting he also stabbed Cornell-Duranleau twice in the lower abdomen and struck him in the head with a side table lamp.

“I don’t know why. I’ll never know why,” Warren said when Assistant’s State’s Attorney Yolanda Lippert asked him why he participated in the July 27, 2017 murder.

Prosecutors are expected to cross-examine Lathem before Judge Charles Burns on Wednesday.

Lathem Tuesday said he had feelings of remorse — not for stabbing Cornell-Duranleau, but for bringing Warren into the couple’s life.

Sobbing, Lathem said he used the dull side of the blade of a drywall saw to engage in “knife play” with Cornell-Duranleau before he was killed. Warren was supposed to record the couple having sex and possibly join in later, Lathem said.

Lathem said he had just given Warren crystal meth and failed to mention that he and Cornell-Duranleau enjoyed BDSM activity.

Cornell-Duranleau and Lathem had also taken the crystal meth, Lathem said.

When Lathem came out the bathroom and saw a dead Cornell-Duranleau, he said, “I wanted to call the police, but I became afraid that the police were going to blame me for this. It’s my boyfriend that’s dead in my bedroom.”

But Lathem said he felt guilt, too.

“I start thinking that it’s my fault,” he said. “I put Andrew and Trent in the same room. I gave Andrew the drugs. I took out a knife without telling Andrew about safe role play with knives. I brought that drywall saw into the bedroom and ... I didn’t stop Andrew from hurting him. I hid in the bathroom like a f––––––– coward.”

That remorse, Lathem said, is what led him to make donations in his boyfriend’s memory at the Howard Brown Health Center and the Lake Geneva Public Library and to record a video message for his parents after he and Warren fled the city.

“I killed him,” Lathem was heard saying on the recording prosecutors showed the jury.

“It wasn’t an accident, but it was a mistake,” Lathem also said on video. “I regret it with every fiber of my being.”

No blood was found on the drywall saw Lathem discussed, although Cornell-Durlaneau’s blood was found on two other knives left in the condo, forensic experts previously testified.

Warren said that when he met Lathem online, he was depressed because of his financial and family struggles and Lathem was “devastated” about not getting a job at the Louis Pasteur Institute in France to continue his research on the bubonic plague.

After Warren arrived in Chicago, he and Lathem drove to St. Louis so they could buy a gun they could use for their suicidal plan, Warren said. But Lathem said it was a trip so they could get to know each other and Warren could see more of the United States.

Lathem’s lawyers have accused Warren of “catfishing” their client, who said the feelings he developed for Warren online dissolved when he saw Warren at O’Hare Airport.

“This is going to sound really shallow but I was pretty disappointed in who I saw,” Lathem said of his reaction to meeting Warren in person.

The five-hour drive south failed to generate sparks, so Lathem said he told Warren he didn’t think their relationship would work out.

This break-up is what prompted Warren to kill Cornell-Duranleau in a jealous rage, defense attorneys have argued.

Lathem said he and Warren did try to kill themselves while they were on the lam, first by connecting their rental car’s exhaust to a hose fed through the car’s window. When that didn’t work, they had hoped to overdose on pills, but were unable to procure them, Lathem said.

The pair eventually made their way to California, where they turned themselves in to authorities — Warren in San Francisco and Lathem in nearby Oakland.