August 5, 2011 -- Three men and a woman are being held for trial in a shooting incident on a Philadelphia city bus after a passenger complained about the woman spanking her child on the bus.

In a preliminary court hearing on Thursday, prosecutors played the dramatic surveillance video that captured the terror on the bus. Men carrying weapons send frightened passengers to the ground, as they scramble for cover.

Authorities say the June 18 violence was triggered when a male passenger, Lafenus Pickett, scolded a female passenger, Penny Chapman, for spanking her child.

"She was spanking her son for something he did," Pickett testified to the court, speaking of Chapman. "I said, 'That's child abuse,'" reported ThePhilly.com.

Chapman then made a call on her cell phone, and three men were waiting for her when she got off the bus in North Philadelphia. Two were armed, one with a long rifle and the other with a pistol. They rushed up to the open back door of the bus and shot 13 bullets into the bus as it drove away.

The driver, Desmond Jones, drove the passengers to the nearest hospital. It turned out nobody had been injured.

"We are very proud of the action that he took to safeguard our passengers," said Jerri Williams, chief press officer of SEPTA (Southeastern Pennsylvania Transport Authority).

The horrifying incident took place on one of SEPTA's busiest lines, route no. 47, which runs from south Philadelphia to north Philadelphia.

The entire incident was captured at various angles on the bus's cameras.

About a third of SEPTA's 1,500 buses are equipped with the technology. Williams says this incident further "validated" the importance of having cameras on board and that the city hopes to have all buses prepared.

A Municipal Court judge has ordered the men and Chapman to stand trial on charges of attempted murder and conspiracy.

Trial is set to begin later in August.