7-year old boy accidentally fires gun on school bus

An 7-year old Mesa, Arizona boy apparently sneaked a gun from home into his school backpack. While he was on the school bus on his way back home, he "manipulated" the gun and it fired. Luckily, none of the 30 kids on the bus were harmed.  (this original article has the age wrong, saying he was 8).

UPDATE (1/9/12): According to that article:

According to a report by KPNX, police and school officials said the weapon was a .22-caliber pistol. 

Parent Mike Place told KSAZ TV he's grateful nobody was hurt. 

"I think it's a miracle for a handgun to be fired in close proximity on a bus and not have any of those students grazed, much less hit," he told the station, "It's a miracle and a blessing thank God none of them were hurt." 

The station reports that the boy acquired the weapon from a closet at home and had the gun with him all day at school.

Every gun in the hands of a child must first pass through the hands of an adult.