Fifty-four-year-old Charles Clark was found dead on Wednesday in his home in Naperville.
Prosecutors say 21-year-old Grant Muren beat him and strangled him. State's attorney Tim Diamond said the two fought after having quote "intimate relations."
Authorities say the suspect moved in after answering Clark's Craigslist posting for a new roommate.
Bond for Muren was set at $2 million over the weekend. His next court appearance was scheduled for February 24, according to authorities.