SAN DIEGO — A San Diego doctor and his wife were fatally shot in their home by their 22-year-old son, who was arrested after he tried to slip past police tape near the scene, police said Saturday.

David Ellis Haynes, 61, and his wife, Lissa Danielle Haynes, 62, were shot multiple times in their Sunset Cliffs home just after 3 a.m. Friday, but the doctor was able to call 911.

When police arrived, the couple was barely alive, and only one was still conscious. Both were later pronounced dead at the University of California, San Diego Medical Center.

Peter David Haynes of San Diego, the couple’s son, was arrested about four hours after the shooting when officers spotted him trying to sneak under crime-scene tape, said Lt. Paul Rorrison. He was armed with a handgun, he said.

There are no other suspects, Rorrison said, and the motive is under investigation.

An autopsy on the victims was scheduled for Saturday, but the results would be sealed, he said.

Detectives were obtaining a search warrant for the home, and there are still many unanswered questions, Rorrison said.

“We’ve been actively investigating this all night, and we just don’t know,” he said. “We’re confident we have our suspect in custody.”

David Haynes had been an emergency room physician for nearly 20 years at the Yuma Regional Medical Center in Yuma, Arizona, according to a statement from the hospital.

“Today we have lost an exceptional physician, colleague and friend – a man who dedicated his life career to caring for patients in our community,” Dr. Phillip Richemont, head of the hospital’s emergency medicine department, said in the statement. “His compassion and kind nature will be extremely missed.”