CHICAGO — Wyndham Lathem, who was found guilty of first-degree murder in the stabbing death of Trenton Cornell, was sentenced to 53 years in prison on Tuesday.

In October, a jury unanimously found the former Northwestern professor guilty of murdering his then-boyfriend in 2017.

Lathem, 47, was facing 20-60 years behind bars.

The presiding Cook County judge called the crime “one of the most cold-blooded, calculated and brutal executions that he has ever seen.”

Before sentencing, Lathem addressed the Cornell family:

Adam Sheppard, Lathem’s defense attorney, addressed the media afterward, stating that his client was unhappy with the judge’s ruling.

“He is disappointed, of course,” Sheppard said. “He exhibited sincere remorse throughout all stages of the case — three arrests, trial and sentencing — and he is trying to remain hopeful.”

Trenton Cornell’s mother also spoke to reporters.

“We are forever grateful to the Cook County Prosecutor’s Office, as well as the Cook County Police Department and the Victims Advocate Office. Their countless hours, days, weeks, months have helped us get some justice for our son,” Charlotte Cornell said. “This is nothing that we would ever wish on any family.”

Before the sentencing, the judge heard motions for a new trial and acquittal but denied both.

Prosecutors successfully proved in court that Lathem was the mastermind behind Cornell’s murder. Andrew Warren, who has already pled guilty and was sentenced in connection to Cornell’s death, 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 the 26-year-old Cornell at Lathem’s suggestion.

Prosecutors say Cornell was stabbed 79 times in Lathem’s River North high rise. Lathem and Warren then drove to California before turning themselves over to police.