KENNEWICK (AP) — Authorities have arrested a 25-year-old man that they say is tied to the killings of an adult and child found badly burned in a car last week.

Franklin County Sheriff Jim Raymond says Prudencio Flagos-Ramirez, of Connell, was booked into jail after his arrest on investigation of murder.

The Tri-City Herald says Flagos-Ramirez was initially arrested on unrelated charges hours after the bodies were found Thursday night in a car down a ravine about a mile off the road.

The sheriff says the man knew the victims but declined to detail their relationships. No motives have been released.

Autopsies are scheduled Monday.

A volunteer firefighter spotted smoke coming from the ravine about 5:45 p.m. Thursday and went to investigate. The firefighter found a car engulfed in flames. The bodies were discovered after the fire was put out.