After a child called police and "indicated" her parents had died, officers found three adults dead in a Fullerton home, Fullerton police said in a statement.
Fullerton police said they received the call around 8:21 a.m. Saturday. They responded to a home in the 400 block of South Gilbert Street where they found two men and a woman dead.
A 17-year-old named Katlynn Goodwill Yost is also missing.
Two children - a 6-year-old and a 10-year-old- were also found in the home, but both were safe, authorities said.
Fullerton police noted the incident was being investigated as a triple homicide as of Saturday evening.
Police say Yost is not a suspect in the killings.
Yost's relationship with the victims was not immediately clear.
Fullerton police was to hold a news conference at 4 p.m. Sunday to provide updates.
Anyone with information about the deaths was urged to call Det. Coffman 714-738-5361, or Sgt. Rowe 714-738-6776, both of the Fullerton Police Department Crimes Persons Unit.
