Mexican zookeeper forgot to shut gate before killed by lion

Authorities say a zoo employee who was killed by a lion in central Mexico may have forgotten to shut a gate that separated the animal's feeding and sleeping areas.

Mexico's office for environmental protection said Monday that an inspection of the enclosure showed no holes or breaches where the animal could have escaped. The lion was being held with a lioness at the Nicolas Bravo zoo in Tulancingo, northeast of Mexico City.

The zookeeper was killed by the animal on March 17 as he cleaned the enclosure. Authorities fired tranquilizer darts but were unable to stop the attack.