(KMOV)-- New details have been released regarding the fatal shooting that happened at the ABB plant in St. Louis 11 months ago.
The investigation report is more than 100 pages long, and reveals information on the incident when Tim Hendron opened fired on his co-workers, killing three and injuring five.
The report states that Hendron had used an AK-47 rifle, a 12 gauge shotgun and two pistols. The rifle and shotgun were purchased just a day before these shootings, officials say.
Police captain Don Sack praised officers for entering the building during Hendron’s shootings saying, “They were able to assist a lot of people out of their hiding spots, and get them out of harm’s way”.
Police say they used a new tactic learned from the Columbine massacre and made the decision to not wait outside the building.
Officials say that initially they weren't able to locate the shooter as he moved through the 700,000 square foot plant firing randomly. They said he was apparently on a mission to kill his supervisor Cory Wilson.
Police don’t have a motive behind the shooting but know that it was planned in advance.