Cell phone and surveillance video captured the July 9 beating, during which Moody calls for help but doesn't step in to stop the fight.
"I got a fight," bus driver can be heard saying in a call to dispatch. "I need help in a hurry, I got a fight I need help in a hurry."
"Get somebody out here quick, quick quick they're about to beat this boy to death. Please get somebody here quick. And they're still doing it. There's nothing I can do," he adds.
Critics wondered why a grown man wouldn't try to pull the boys apart.
"There was clearly an opportunity for him to intervene and or check on the welfare of the children or the child in this case and he didn't make any effort to do so," Gulport Police Chief Robert Vincent said.
School policy only requires the driver to call dispatch, and Moody said he was too afraid to intervene physically.
"The three boys just jumped on him and started pounding on him. And I did all can," he said. "I was looking. It was like I was in shock. I was petrified."
Moody's attorney Frank McDermott called child neglect accusations "preposterous."
"I don't think law enforcement should ever tell citizens to intervene in a violent attack. John did what he was trained to do," McDermott said.
All three teenagers who instigated the attack were charged with aggravated battery.