Excerpt from CBSNews:
William Balfour, a man suspected in the deaths, was arrested Friday but had not been charged, law enforcement sources told the Chicago Tribune and Chicago Sun-Times.
Police spokeswoman Monique Bond said investigators were talking to "a number of people in custody" but she declined to elaborate.
Paul Ciliano, a former Chicago police officer and CBS News consultant, said the Englewood neighborhood where the crimes were committed is "probably the toughest neighborhood in the city of Chicago.
"This is notoriously violent area, the most shootings and car hijackings and tough-and-rumble place on the South Side of Chicago," he told Early Show anchor Priya David.
Ciliano said the first priority of the police right now is locating the missing boy. "That's their focus. They have the suspect, the number one suspect (and only suspect as far as I know) in custody, so right now all their efforts are going towards finding and locating this child and getting him home safely."
Police say Balfour took Donerson's 7-year-old grandson Julian King with him when he fled.
Balfour's mother, Michelle, said her son had been married to Hudson's sister, Julia, for several years, but they were separated. She also said Donerson had ordered him to move out of the family's home last winter.
The Cook County medical examiner's office said autopsies for Donerson and Jason Hudson were pending.
The boy, who may have witnessed the murders, has not been found.
Her sister, Julia, met police at Wentworth Area headquarters late Friday.
UPDATE Via TMZ:
TMZ has spoken with several other neighbors this morning who say Julia complained to them that William Balfour sold one of their cars without permission. One neighbor told TMZ the dispute got so heated William threatened to "kill Julia's family" but she didn't report it because she didn't take it seriously.
As for the dispute over the car being the trigger, our sources say cops are pursuing the lead but are looking at everything.
And our law enforcement sources say people other than Balfour have been interviewed as well.
UPDATE Via ChicagoBreakingNews:
Police believe the murders happened about 11 a.m. and started outside with the gunman firing through the door and striking Hudson's brother, according to a law enforcement source. The gunman then entered the house and continued to fire, striking Hudson's mother when she entered the room. Police have recovered shell casings from the scene.
Police said neighbors heard the shots but didn't call police because gunfire is commonplace in the neighborhood.
Jennifer Hudson had been trying to convince her family to move out of Englewood, the source said, but they wanted to continue living in the neighborhood.
Wentworth Area detectives were handling the investigation.
Jennifer Hudson visited the Cook County Medical Examiner's Office overnight with other family members to identify the bodies of her mother and brother, according to the office.