An Oxford University employee has been arrested alongside a US professor following a nationwide manhunt for the murder suspects, police have said.
Somerville College senior treasury assistant Andrew Warren, 56, and Professor Wyndham Lathem, 42, were in custody on Friday in Oakland, California, more than 2,000 miles from the crime scene.
They have been accused of fatally stabbing Trenton Cornell-Duranleau, 26, in Lathem's apartment in Chicago on July 27.
Warren was arrested in San Francisco while Lathem was arrested in Oakland, US Marshals inspector Ed Farrel told the Chicago Tribune.
Chicago Police spokesman Anthony Guglielmi said: "Wyndham Lathem and Andrew Warren have both been arrested in California.
"We got word within the hour that they have both been captured and are in police custody.
"Both individuals will be held accountable for their actions and we hope today's arrest brings some comfort for the victim's family. We are also thankful that this did not end in further tragedy."
The men will appear in court in Oakland before being returned to Chicago where they will be interrogated by detectives, the spokesman added.
Oxford University had urged Warren to hand himself in and a spokesman said his colleagues were "shocked" to have heard of the case.
Warren, who says on Facebook he lives in Swindon, Wiltshire, and Lathem, a microbiology professor at Northwestern University, are accused of repeatedly stabbing the victim in the 10th floor apartment before fleeing.
Detectives said they believed they knew their whereabouts but wanted to end the situation calmly without another "tragedy".
Mr Cornell-Duranleau is a hairstylist originally from Corunna, Michigan, but was living in Chicago at the time of his death.