DIAMOND BAR (CBSLA) – Neighbors in Diamond Bar woke up to crime scene tape and a lot questions as word quickly spread that two people were killed inside their home.

Investigators said it is a mother and her adult son who died. It happened Friday around 10 p.m. Deputies got a call from a relative inside the home who did not live there.

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“It’s very tragic,” said Sally Fidel, a neighbor. “I have two sons myself and we’re just really praying for the family and hoping they find out exactly what happened.”

Both the 55-year-old woman and her 23-year-old son had signs of trauma, which is why investigators are calling it a homicide.

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“We’re not sure what weapon was used at this point, or how they died,” said Sgt. Chris Bergo of the LA County Sheriff’s Department.

Deputies added they had been dead for some time.

“I think that’s what’s scary, one police officer told my husband they don’t believe it was a robbery, but we don’t know any more details,” added Fidel.

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The coroner’s office will investigate to give a cause of death and timeline.