CHICAGO — A judge sentenced a former Northwestern University professor to 53 years in prison Tuesday for the 2017 stabbing death of his boyfriend.

Cook County Judge Charles Burns called the killing of Trenton Cornell-Duranleau “coldblooded” and an “execution” as he sentenced Wyndham Lathem, 47, who was found guilty of first-degree murder in October.

Cornell-Duranleau was stabbed more than 70 times on July 27, 2017, by Lathem and Andrew Warren, a British man who Lathem had paid to come to Chicago to commit the murder together, prosecutors said.

Northwestern fired Lathem, a renowned microbiologist, after he fled the Chicago area following the killing.

Lathem testified during his trial that Warren alone stabbed Cornell-Duranleau during what started as a methamphetamine-fueled sexual encounter involving the three men.

Warren in 2019 pleaded guilty to murder under a plea agreement that called for him to testify against Lathem in exchange for receiving a 45-year prison sentence.

Warren, who was an Oxford University financial officer at the time of the slaying, testified that he flew from England to Chicago to meet Lathem and take part in a pact to kill each other before agreeing to kill Cornell-Duranleau at Lathem’s suggestion.

He testified that he did, in fact, stab Cornell-Duranleau, but only after Lathem had already begun stabbing him.