(CNN) -- Two women and two children were found dead in an San Clemente, California, home in what police believe was a murder-suicide, authorities said.
The owner of the home -- who lives nearby and leases the home to one of the women -- called the Orange County Sheriff's Department at 1:43 p.m. Monday and told police he had heard a disturbance there and was concerned about the safety of the two children, sheriff's spokesman Jim Amormino said.
Authorities arriving at the home found the bodies inside, Amormino said. The victims were a 2-year-old girl, her 4-year-old sister, the children's 38-year-old mother and a relative in her 60s who was leasing the home, he said.
Police are not sure who is responsible for the deaths, but they believe it was one of the two women, Amormino said. Asked whether the incident was a murder-suicide, he said, "That's the theory we're going on," and added that the investigation was ongoing.
It is very unusual to have a murder-suicide where everyone involved is female, Amormino said. He said it is also unusual for the neighborhood, a gated community with million-dollar homes.
Amormino said these are San Clemente's first homicides this year.
"I've been in this business 38 years," he said. "Any time children are involved, it just tears at your gut."