A Gun?

Where did this child get the gun it was carrying?  Can you imagine the outcome of this situation.  News has it, that a "Kindergarten student" had a gun in it's pocket and the gun fell out while the child was in the lunchroom at Ross Elementary in Houston, TX.  Three children were injured, when the gun discharged.  Bullet fragments hit the child and two other students when it discharged.  None of the injuries were listed as critical.
I can't imagine a small child being able to get to such a thing.  What were the parents doing, during this whole time?  How awful and stupid of the parents to be so irresponsible.