The Cook County State's Attorney's Office said the plea agreement has been sealed, but did confirm the guilty plea and that Warren's prison sentence is contingent upon his statement at Lathem's trial.
Both were charged with first-degree murder for the death of 26-year-old Trenton Cornell-Duranleau at the Grand Plaza Apartments in River North in 2017.
"What they discovered in that apartment can only be described as savage and grisly," Chicago Police Superintendent Eddie Johnson said at the time.
The apartment belonged to Lathem. Prosecutors said on July 27, 2017, Warren and Lathem lured Cornell to Lathem's apartment where the two carried out a "twisted sexual fantasy" that resulted in the young man's stabbing death. Police said Cornell was stabbed more than 40 times, and suffered "lacerations and mutilations to his body, his upper body, but not to the point of decapitation," police said at the time.
The attack was so brutal the blade of the knife police believe was used in the stabbing was broken. His body was found at least 12 hours after he was killed.
Warren and Lathem then fled, leading state and federal law enforcement on a cross-country man hunt. They were arrested nearly two weeks later, on August 4, 2017, when Warren turned himself in to San Francisco police. Lathem surrendered himself to US Marshals at a federal courthouse in Oakland, California, just an hour later. They were sent back to Chicago.
If Warren complies in Lathem's trial, the state's attorney's office will recommend a 45-year prison sentence.
Warren is expected to appear in court Tuesday. The state's attorney's office said the judge may rule on whether or not to unseal his plea agreement.
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