An Oxford University employee has pleaded not guilty to a Chicago stabbing death that prosecutors called "exceptionally brutal".
Andrew Warren, 56, appeared in court on Thursday alongside co-defendant Wyndham Lathem, a 46-year-old former Northwestern University professor who also denies the charge.
Defence lawyers entered pleas on their behalf.
The men are charged with first-degree murder over the July death of 26-year-old Trenton James Cornell-Duranleau, a hairstylist who authorities say was Lathem's boyfriend.
Lathem and Warren surrendered to authorities days later in California and remain in jail.
Prosecutors said Cornell-Duranleau was in bed in Lathem's Chicago apartment when the men allegedly stabbed him dozens of times in what was part of an apparent sexual fantasy.
They said on Thursday they plan to seek an extended sentence because the murder was part of a "preconceived plan".