VALLEY SPRINGS -- Residents of rural Calaveras County are being told to keep their doors locked as authorities continue to search for the killer of a 9-year-old girl.

Calaveras County deputies and law enforcement officials from nearby agencies are looking for a suspect after the girl was found stabbed in her Valley Springs home around noon Saturday.

Sheriff's officials say the girl was found by her brother after he encountered an intruder in the home. When the intruder ran away, the boy found his sister stabbed. She was pronounced dead at a local hospital.

The name of the girl has not been released. Authorities spent the night and into Sunday morning in a door-to-door sweep of the area. They're also interviewing several people, but no suspects have been identified.

Valley Springs is about 60 miles southeast of Sacramento.