Chicago police are looking at the movements of their only suspect on the day three relatives of Chicago-born singer-actress Jennifer Hudson were killed.

Law enforcement sources say evidence suggests that more than one person may have been involved in the shooting deaths of Hudson's mother, brother and 7-year-old nephew, the Chicago Tribune reported Wednesday.

The sources told the newspaper investigators are trying to determine whether someone drove convicted felon William Balfour, identified as a person of interest, to the city's West Side after the killings at the Hudsons' South Side home.

They are also looking into conflicts between Balfour and his estranged wife, Jennifer's sister Julia, and other members of the Hudson family.

"No means did my son do this," Balfour's mother Michele Davis-Balfour told CNN. "My son's alibi was (he was) with one of his girlfriends, OK?"

Davis-Balfour also denied her son had a stormy relationship with Julia Hudson, claiming the couple were together Thursday night to celebrate Julia Hudson's birthday.