The tragic story of the slaying of Jennifer Hudson’s family begins to slowly unfold. Police investigators said they have strong arguments to believe that there was more than one person involved in the crime. Police officials told the Chicago Tribune today that they might want to look for more than one person, but for now the investigation remains focused on the estranged husband Hudson’s sister Julia, William Balfour.

Investigators are trying to find out whether another person drove Balfour to the West Side of Chicago after the killings took place in South Side. Balfour is still in jail, but on unrelated charges. The 27-year-old man is an ex-convict. He served almost 7 years in prison and last week was found with cocaine on him. The investigation is now focused on what Balfour did that day (Oct. 24) and if he was accompanied by someone else.

According to some eyewitnesses, Balfour drove his Chrysler to the South Side block around 7 a.m. on Friday, but the car was found parked about a mile away from the home where Hudson’s mother and brother were found shot dead that day. The person who parked the vehicle there can be seen on some security videos, but investigators were unable to identify the driver.

According to records of the man’s cell phone, Balfour was on the West Side at that hour, sources told the Chicago Tribune. If the records prove to be accurate, it would mean that another person may have driven his Chrysler from the home in South Side to the school located about one mile away.

Balfour could have been in jail at the time of the crime. He should have been sent to jail for parole violation and cocaine possession, but police chose to allow him to remain free.

No one has been charged in the killings yet.