The newspaper, citing the police sources, reported Michael Ward, 18, told investigators Pendleton was shot by mistake. He allegedly said he and Kenneth Williams, 20, believed a group of young people hanging out in Harsh Park were members of a rival street gang.
The shooting attracted national attention because Pendleton was a majorette with her school's marching band, which had performed at President Obama's inauguration a few days earlier. She was also gunned down about a mile from the president's home in Chicago.
Ward and Williams, reputed members of the Gangster Disciples, were arrested late Saturday. Sources told the Tribune investigators got a tip from a jail inmate that a recent parolee might have information and the parolee then led them to the two suspects.
The gun used in the shooting has not been recovered. Jennifer Sexton, an assistant state's attorney, said in court Tuesday that security footage shows a white Nissan Sentra, allegedly one owned by Ward's mother, near the park, and that eyewitnesses have identified Williams as the driver.
Ward allegedly admitted being the shooter, saying he got out of the car and approached Pendleton and her friends quietly, believing they were gang rivals. Pendleton was shot in the back and two of her friends wounded.
Pendleton's parents attended Tuesday night's State of the Union address, where Obama pointed them out as victims of gun violence.