An investigation is underway at the Pittsburgh Zoo after a toddler was killed there Sunday.
The 2-year-old boy fell 11-feet into the African painted dog exhibit.
The boy's mother had lifted him onto a railing on an observation deck above the dogs' habitat.
Police say the boy fell almost immediately into the enclosure and the dogs attacked.
Investigators are still trying to determine whether he died in the attack or from the fall.
Zoo staffers responded to the situation very quickly but they weren't quick enough to save the boy.