In connection with the July 27 death of 26-year-old Trenton Cornell-Duranleau, a judge issued arrest warrants for Lathem and Warren, charging them with first-degree murder.
Police say last Thursday around 8:30 p.m., a maintenance worker at Lathem's apartment building in the 500 block of North State Street called 911 after getting an anonymous tip that a crime had happened in a 10th floor apartment.
Warren is listed as senior treasury assistant at Somerville College, which is part of England's Oxford University network.
On Wednesday, Chicago police spokesman Anthony Guglielmi said detectives suspect the pair may have fled IL and their passports have been flagged by the State Department.More news: Indian Women's Cricket Team Receives Immense Reception from Crowd at Mumbai
Lathem, who has been on staff at Northwestern for a decade, has been placed on administrative leave and banned from entering Northwestern campuses.
Police spokesperson Anthony Gugliemi issued an appeal on Wednesday, asking the men to "do the right thing and turn yourself in" as the search "will only intensify". The medical examiner's office said he died of multiple sharp force injuries.
"Lathem has been a faculty member in the department of microbiology-immunology since 2007", the statement said.
Lathem is friends with the victim on Facebook but their relationship is not yet clear. Cornell-Duranleau, who was living in Chicago, was licensed as a cosmetologist in his native MI, according to Michigan's Department of Licensing and Regulatory Affairs.More news: Trump's Foreign Policy Is Jeopardized After Senate Approves Sanctions Against Russia
In an obituary posted on her Facebook page, his mother, Mischelle Duranleau, said he was born in the small town of Lennon, Michigan, and loved animals, music, cars and video games.
A statement from Oxford University said it was "not aware of this case, which is clearly extremely concerning", reports the Chicago Tribune. "Trenton was a caregiver and loved to help others", Duranleau wrote. "We will liaise with the relevant investigating authorities and provide any assistance that is required".
In his LinkedIn profile, Lathem said his research is focused on pathogens and the diseases they cause.More news: Iran`s Hassan Rouhani sworn in for second term