(CNN) -- The stepdaughter of Jesse Browning, the star of a reality show about loggers, was attacked and killed by the family's dog in Astoria, Oregon, an investigator said.

Her mother found 4-year-old Ashlynn Anderson in the yard of their home after the attack Sunday afternoon, Clatsop County Sheriff Chief Deputy Paul Williams said Tuesday.

The child was pronounced dead on arrival after she was flown by helicopter to a Portland hospital, Williams said.

The family's two Rottweilers were placed in quarantine, he said.

The dog believed to have bitten the child was 2½ years old, he added.

Ashlynn's stepfather, Jesse Browning, is a logger who appears on the reality show the History Channel describes as a series about "the treacherous life of Pacific Northwest timber cutters."