Australian police said Friday that a 7-year-old boy who went on a 35-minute killing spree in a reptile park was too young to face criminal charges.

The schoolboy on Wednesday broke into the Alice Springs Reptile Centre, cracked open cages and fed 10 live exhibits to the park's resident crocodile. He was also seen on security cameras bludgeoning to death three lizards.

Centre director Rex Neindorf told the Northern Territory News that the cruelty was "disgusting."

"I'm just devastated at the age of the child and the fact no one wants to take responsibility," he said.

A turtle, four western blue tongue lizards, two bearded dragons, two thorny devils and a 1.8-metre Spencer's goanna were thrown to their deaths in the crocodile pen.