CARY, Ill. (AP) — A 10-year-old boy was in critical condition Sunday after three pit bulls escaped from a home and went on a rampage, attacking six people before police shot and killed the dogs, authorities said.

No charges had been filed Sunday, but McHenry County Sheriff Keith Nygren said it was being investigated as a crime scene.

Neighbors said the attacks started late Saturday afternoon when children going door-to-door for a fund-raiser arrived at the home of Scott Sword, 41, who owned the dogs.

The pit bulls attacked the two children, and when the dogs' owner tried to stop them, the dogs turned on him and bit off his thumb, Nygren said. The boy's father also tried to protect his son and was attacked.