Somerville College have urged their employee accused of stabbing to death a hairstylist in Chicago to turn himself in to US authorities as police in Chicago said they were “closing in” on him and a US academic.Police in the city said they “have an idea” of the whereabouts of Andrew Warren, a senior treasurer assistant at Oxford’s Somerville College and Wyndham Lathem, a professor at Northwestern University. The pair are accused of stabbing to death a 26-year-old-man, Trenton Cornell-Duranleau, in Lathem’s Chicago apartment.Oxford University said it would help police with their investigation as Somerville College urged Warren to turn himself in.“Andrew Warren’s colleagues at Somerville College have now all been informed and are shocked to learn of the case,” a college spokesperson said.“Whatever the circumstances, we would urge him to contact the US authorities as soon as possible, in the best interests of everyone concerned.”Officers in Chicago said their hunt for the Warren, 56, and Lathem, 42, a microbiology professor, was “intensifying”.“We do have an idea of their whereabouts and efforts to locate them are only intensifying from here on in,” a spokesperson said.“Our primary focus is to facilitate a safe surrender and we strongly encourage Professor Lathem and Mr Warren to do the right thing.”Officers found the victim with multiple stab wounds in Lathem’s 10th floor apartment on 27 July. The attack was so violent that the blade of the knife believed to have been used to stab Cornell-Duranleau had broken, Chicago police said.US police warned members of the public that the because of the violent nature of their alleged crime, the pair were believed to be “armed and dangerous”.Warren, 56, oversaw pensions and payrolls at Somerville. According to police and media reports, he is believed to have flown to the US days before the murder took place, after allegedly meeting Lathem online.Court files give Warren’s address as Somerville but his Facebook profile says he lives in Swindon, Wiltshire and is a former cashier and Stagecoach bus driver.In an email sent to Somerville staff and students on Tuesday morning, the college Principal, Alice Prochaska said: “Neither the College nor the university were aware of the case, which is clearly extremely worrying. We and the university authorities will liaise with the investigating authorities and provide any assistance that is required.“This comes as upsetting news to all of us. Counselling support can be made available to anyone who needs it.”In a statement on Thursday, Oxford University said it had been in contact with police in the UK about Warren and was “ready to help the US investigating authorities in any way they need”.His alleged accomplice, Wyndham Lathem, had worked as a scientist at Northwestern University since 2007, specialising in the bubonic plague.Northwestern said Lathem had been placed on leave and was banned from entering the campus.