The convicted felon suspected in the slayings of Oscar-winner Jennifer Hudson's mother, brother and nephew was arrested after police allegedly found crack cocaine in his car in June, but authorities declined to return him to prison on a parole violation, according to documents obtained by The Associated Press.

A judge dismissed the charge for lack of probable cause in July, but under the strict rules of the state's parole program, William Balfour could have gone back to prison just for the arrest.

No one has been charged in the shooting deaths of Hudson's mother, Darnell Donerson, her brother, Jason Hudson, and 7-year-old nephew Julian King, but Balfour has been named as a suspect. Chicago Police Superintendent Jody Weis said Tuesday he is confident the case will be solved.

Balfour — Julian's stepfather and the estranged husband of Hudson's sister — served seven years for attempted murder and vehicular hijacking. Court records show that in 1998 Balfour stole a Chevrolet Suburban and, with the vehicle's owner clinging to the top, intentionally rammed it into a light pole, fence and iron gate.

This undated photograph, released by the Illinois Department of Corrections October 25, 2008, shows William Balfour. Balfour, 27, reportedly had a relationship with Hudson's sister and is the father of King. [Xinhua/Reuters]

According to a Chicago police report, officers pulled Balfour over June 19 after hearing gunshots and seeing his car moving at a high rate of speed. Inside the vehicle, police said, they found a rock of cocaine with a street value of about $100 on the driver's seat.

Balfour's parole history report indicates a parole supervisor declined to issue a warrant to revoke Balfour's parole after his arrest for possession of cocaine.

"Per supervisor ... no warrant," the report reads. "Agent to monitor offender, impose sanctions."

Corrections Department spokesman Derek Schnapp said officials determined "the evidence that was presented during that time wouldn't have necessarily warranted a violation."

Court records do not indicate the reason a judge found no probable cause for the drug arrest.

A felony arrest usually is enough for Corrections to revoke parole, said Thomas Peters, a Chicago criminal defense attorney who represents parolees.

"Even though the criminal case is dismissed does not mean that you necessarily get a pass on a parole violation because the standard of proof is much less," Peters said.

Peters added, however, that officials also would have considered Balfour's fairly clean record as a parolee and that he apparently still had a job. In addition, he said, jail and prison overcrowding often play a role in determining whether parole is revoked.

Donerson, 57, and Jason Hudson, 29, were found in their home Friday afternoon. The body of Julian, who lived with the other victims, was found in the back of an SUV on Chicago's West Side on Monday. Authorities declared his death a homicide Tuesday but would not say how long he had been dead.