Two university employees wanted over the stabbing death of a Chicago man have surrendered peacefully in California and will be returned to Chicago for interrogation, authorities said.
Wyndham Lathem, 42, gave himself up late on Friday at the Oakland federal building and Andrew Warren, 56, surrendered at about the same time to the San Francisco Police Department, according to Michael McCloud of the US Marshals Service.
Mr McCloud said the surrender of the two suspects was "negotiated", although he declined to say how it happened.
"We were not in contact with them directly," he said.
Lathem, an associate microbiology professor at Northwestern University, was booked into the Alameda County jail.
Warren, a Somerville College employee at Oxford University in England, was taken to San Francisco County Jail.
They will appear separately in court before being extradited to Illinois.
A manhunt had been under way since shortly after the body of 26-year-old Trenton James Cornell-Duranleau was found with stab wounds on July 27 in the Chicago apartment where Lathem lived.
"Both individuals will be held accountable for their actions and we hope today's arrest brings some comfort for the victim's family," a Chicago police statement said.
Police said Lathem had sent a video to friends and relatives apologising 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.
"We are also thankful both men are safely in custody and this did not end in further tragedy," the police statement said.
Warren had arrived in the US three days before the killing and was seen in surveillance video leaving the building with Lathem on the day of the stabbing.
Mr McCloud said the US Marshals Service learned on Wednesday that the two men might be in the San Francisco Bay area.
Police said Lathem had a personal relationship with Mr Cornell-Duranleau, who moved to Chicago from Michigan after receiving his cosmetology licence.
Detectives are not sure how they knew Warren, or if Warren knew them before he flew to the US.
In a bizarre twist, police said that on the day of the killing, but before the body had been discovered, Lathem and Warren drove about 80 miles north west to Lake Geneva, Wisconsin, where one of them made a 1,000 dollar cash donation to the public library there in Mr Cornell-Duranleau's name.
Lake Geneva police said the man making the donation did not give his name.