An 11-year-old boy in Iowa is suspected of intentionally killing three animals with a lethal injection of insulin.

KCCI reports that an 11-year-old boy in Marshall County is believed to have intentionally caused the deaths of two dogs and a cat. According to the news station, the boy’s mother called police on Thursday, July 12, to report her son behaving erratically.

When police arrived, they found the three animals barely breathing, and called in a volunteer animal rescue agency.

“We walked up to the house and we actually had all three animals laid out on the sidewalk,” Austin Gillis, a volunteer animal rescuer, told the news station.

“We needed to get those animals medical attention immediately or there was no hope.”

A veterinarian attempted to save the animals’ lives, but after a day all three had died.

The boy’s mother reportedly has an insulin prescription, and police believe the boy took the drug from her supply. Three empty vials of insulin were found near the animals.

Prosecutors are expected to file charges against the boy this week.