Officers in training performing a grid search found a weapon in thick shrubs, said Deputy Chief Nicholas Roti. The gun was sent to the Illinois State Police crime lab for more testing.
"There was also some small bits of evidence recovered," Roti said. He did not elaborate and declined to take questions.
Dozens of officers combed the blocked-off area and searched through brush and trash. Roti said police have been conducting systematic searches near sites related to the crime.
While police recovered evidence, investigators were looking into the possibility that more than one person was involved in the murders of Jennifer Hudson's mother, brother and nephew, according to reports.
Chicago police sources tell ABC7 that at this point there is not enough evidence to say whether there may have been more than one killer, but they are not ruling out that possibility.
Members of the Hudson family returned to their Englewood home briefly Tuesday night to retrieve some possessions while a crowd of friends and neighbors prayed for them outside.
Police continue to focus their investigation on 27-year-old William Balfour, the estranged husband of Jennifer Hudson's sister. Police are calling him a person of interest.
A family friend said that Balfour had been thrown out by the Hudson family and often went on angry tirades.
Friday afternoon, the same day Jennifer Hudson's mother and brother were murdered, Balfour missed an appointment with his parole agent, reportedly because he was babysitting.
Amanda Archie lives on Chicago's West Side, close to the crime scene where 7-year-old Julian King's body was discovered in the white SUV that belonged to Jennifer Hudson's slain brother, Jason.
Archie says she saw the SUV pull up on Friday.
"I was parked on Kolin right after you come down 13th Street," Archie said. "This white truck, it went around the block two times, and it came back to Kolin. It went down Kolin coming down this way, and then it parked in front of a old, white, raggedy van."
Archie says the SUV looked suspicious. She watched it for a while then saw two men exit the truck. She says she was too far to see their faces.
"A few minutes later, two guys got out of the van and walked this way back towards 19th Street," Archie said.
The Chicago Tribune is reporting that police are looking into the possibility that there was more than one killer. Police Superintendent Jody Weis again expressed confidence that detectives are close to catching the killer or killers.
"Our detectives are continuing to work around the clock, following up what any possible leads might be available and out there. We will solve this case," Weis said Tuesday.
"I really don't think one person could have came and did this and then got away. It's more than one involved. I do believe that," said neighbor Angela Eli.
ABC7 has learned that Balfour has an extensive and violent arrest record. He served almost seven years in prison for attempted murder. He has a parole hearing scheduled for November 10. A hearing officer will decide if he violated the terms of his parole regarding anger management and substance abuse. It is important to note, however, that so far he has not been charged in this case.
Balfour's own teal Chrysler was found by police parked about a mile away from the Hudson home, outside Robeson High School, 6835 S. Normal Blvd.
Sources say no other evidence, including DNA and fingerprints, link Balfour to the crime.
The Associated Press contributed to this report.