CHICAGO (AP) — An Oxford University employee accused of killing a 26-year-old hair stylist was extradited to Chicago late Friday night.

Oxford University financial officer Andrew Warren arrived in Chicago just before midnight from California.

He and 43-year-old Wyndham Lathem, a former Northwestern University professor, face charges of first-degree murder for the death last month of Trenton James Cornell-Duranleau, a Michigan native who had been working in Chicago.

Authorities say Cornell-Duranleau suffered more than 40 stab wounds to his upper body during the attack in Lathem's high-rise Chicago condo.

Lathem and Warren, 56, surrendered peacefully to police in northern California on Aug. 4 after an eight-day, nationwide manhunt.

Investigators say Lathem had a personal relationship with Cornell-Duranleau.

It's unclear what the relationship was between Lathem, Cornell-Duranleau and Warren, who's British. He arrived in the U.S. three days before the killing, after being reported missing in Great Britain.

Lathem, a microbiologist who's been on Northwestern's faculty since 2007 but was not teaching at the time of the attack, was terminated by the university for fleeing from police when there was an arrest warrant out for him.

Investigators said at some point after the killing, Lathem sent a video to friends and relatives apologizing for his involvement in the crime, which he called the "biggest mistake of my life." The video raised concern among investigators that Lathem might kill himself.

Lathem and Warren both appeared in court in California last week, where they agreed to return to Illinois to face charges.

An attorney for Lathem, Kenneth H. Wine, called him a "gentle soul" and said "what he is accused of is totally contrary to the way he has lived his entire life." Wine said Lathem intends to plead not guilty to the charges.

Warren was represented by a public defender during a brief appearance in a San Francisco court. She said he is "presumed innocent," but declined to comment further.