A Northwestern University professor, wanted for a brutal stabbing in his Near North Side apartment, has sent a video message to family and friends apologizing for "his involvement" in the slaying, police said Friday.



The disclosure is the latest twist in the slaying of 26-year-old Trenton Cornell-Duranleau, who was found repeatedly stabbed and slashed in the home of Wyndham Lathem on July 27.



On Thursday, police said either Lathem or another suspect in the case, Andrew Warren, made a $1,000 cash donation in Cornell-Duranleau's name at the Lake Geneva Public Library on the day of the slaying. The person gave no indication why the contribution was being made.



Both men, who are wanted on charges of first-degree murder, remained at large Friday, though police say they have an idea where they might have fled. Lathem, 42, is an associate professor of microbiology at Northwestern and Warren, 56, is an employee of Oxford University in England, who traveled to the United States for the first time just three days before the slaying.



"We believe they're together or (at) least in very close communication," said Anthony Guglielmi, chief spokesman for the Chicago police.



Guglielmi would not say when the video was made or when it was sent out. In it, Lathem said he had made "the biggest mistake of his life," Guglielmi said, declining to release further information. He urged Lathem to turn himself in.



"At this point, he's reached out to family and friends," Guglielmi said. "We don't want to see this get any worse."



Police believe Cornell-Duranleau was killed in Lathem's apartment in the 500 block of North State Street around 5 a.m. on July 27. But officers were not alerted until an anonymous caller reached the front desk of the building around 8:30 p.m., more than 15 hours later.



They found Cornell-Duranleau lying face down, dead from stab wounds to his back, law enforcement sources said. In the kitchen, police found a knife with a broken blade in the trash can and another knife near the sink. Blood was everywhere, the sources said.



Police said they suspect Lathem fled with Warren. Both men were seen on surveillance video at the building, police said.



Around 5 p.m. that day — more than three hours before the body was discovered — one of the suspects walked into the library in Lake Geneva, Wis., and approached the circulation desk, according to Lake Geneva Police Lt. Edward Gritzner.



The man told a staffer he wanted to make a donation in the name of Cornell-Duranleau but asked to remain anonymous. The staffer accepted $1,000 in cash from the man, who turned and left through the main door.



No one saw him get into a car.



The man did not specify what he wanted the money to be used for, and Gritzner described it as a "general'' donation, nothing unusual for the library.



"They do take donations, a lot, as a matter of fact," he said. "Accepting a donation is not uncommon."