Philadelphia prosecutors claim that Penny Champan triggered a violent shooting because a fellow bus passenger threatened to report her for spanking her child.

Security camera video shows Chapman making a call on her cell phone shortly after the man threatens to report her for child abuse.

Several minutes later, Chapman exits the bus and several men open fire on the vehicle with an assault rifle and a handgun, according to MyFoxPhilly.com. At least five bullets were fired through the back of the bus and several more came through the side, prosecutors said.

Defense lawyers argued that the gunmen should not have been charged with assault because no one was injured.

Watch this video from MyFoxPhilly.com, broadcast Aug. 5, 2011.

Video Shows Dramatic Septa Bus Shooting: MyFoxPHILLY.com