A wild Wednesday night shootout at an Altgeld-Gardens convenience store was a dispute over money, a law enforcement source with knowledge of the investigation told NBC Chicago.
Sources said the store -- The Connect -- had been buying property off the street, some if it apparently stolen, and then re-selling it at their store.
Wednesday night's shooting, which left four men dead and a woman injured, came after an argument erupted after store employees refused to pay up for property previously given to the store.
The patrons involved in the argument left and returned to the store minutes later with guns ablaze. A source compared it to "a tactical assault on a building."
There were seven people in all, four with weapons, including an assault rifle, a source said. The gunmen quickly took out the most obvious threat, killing the store's security guard. They then fired at employees behind the counter, who fired back, hitting one of the original shooters.
A minute later, the shooters left the store only to learn they'd left a man behind. They returned and exchanged more gunfire. A third employee was killed and another shooter hit.
The original shooters all fled to Roseland Hospital, sources said, where one was pronounced dead and another treated for gunshot wounds. Five others were taken into custody by police and are now being questioned as "persons of interest" by Area 2 police.
The narrative told by NBC Chicago's sources seems to coincide with remarks made by Ald. Anthony Beale (9th), whose district includes the store. Beale said he felt the shooting wasn't random but was rather a personal vendetta.
"The community should definitely be upset and concerned, but not too alarmed because this was something that was personal and not and that could not have been avoided because this was something between personal individuals," he said at a press event announcing a massive Chicago Transit Authority rehabilitation project.
Sources said the store was so badly damaged by gunfire that police were still counting all of the shell casings as of 7 p.m. Thursday. Police are also reportedly in the process of obtaining a search warrant to look a garage next door to The Connect, where the store kept some of its merchandise.
That warrant may be obtained and carried out Friday morning.
An attempt to reach the store's manager for comment was unsuccessful.