Chicago police say evidence shows the Hudson family murderer may have had help.

Hours after the bodies of Jennifer Hudson’s mother, Darnell Donerson, and brother, Jason Hudson, were found shot to death inside their home, police issued an Amber Alert for Hudson’s missing 7-year-old nephew, Julian King, along with two cars.

Police now say William Balfour, the estranged husband of Hudson’s sister Julia Hudson, drove his teal Chrysler to the Hudson home in Englewood on the South Side of Chicago around 7 am Friday. He had argued over the phone with Julia Hudson earlier that morning.

Cops later found the Chrysler parked about a mile from the residence. A grainy security video obtained by police shows someone parking the car outside Robeson High School.

A time stamp on the video shows the car was left there at 12:30 pm Friday. Police were unable to determine the identity of the individual getting out of the car. Balfour’s cell phone records place him on Chicago’s West Side at that hour.

Police arrested Balfour at his pregnant girlfriend’s house on the West Side, about 5 hours after the bodies were found.

A neighbor who lived on the street where Balfour was arrested, saw a man fitting Balfour’s description park a white SUV across from his home on Friday a few hours before the bodies were found.

The white SUV matched the truck that was listed on the Amber Alert. Julian King’s body was found Monday on the floor behind the driver’s side seat of a white SUV parked on the West Side about two miles from Balfour’s girlfriend’s house.

Autopsy results revealed the boy had been shot twice in the head.

Balfour’s girlfriend disputes his alibi and he was caught in at least one other lie. Balfour, who has not been charged in the case, stopped cooperating with police when they asked him to take a lie detector test.

He is currently being held at a state correctional facility on a parole violation.