Suspect Arrested in 30-Year-Old Cold Case

The suspected gunman in the 1980 murder of a Santa Monica teenager is in custody after a two-year investigation by investigators who worked the cold case "using old fashioned detective" skills.

Patrick David Salmon, 53, was arrested two weeks ago at his home in Shaler Township, PA, a suburb of Pittsburgh, and is awaiting extradition to Los Angeles, the Santa Monica Police Department announced Thursday.

Joaquin Mansion, 16, was shot to death during a home-invasion robbery May 21, 1980 in the 700 block of Marine Street. Two juveniles were convicted of robbery and murder in the months following, but the adult gunman, a transient known to acquaintances only by a nickname, was never identified.

The investigation was ultimately suspended for nearly three decades until it was reopened by Santa Monica's Police Department's Cold Case Unit two years ago.

"Unlike typical cold cases, this one was not solved with DNA," said Sgt. Richard Lewis. It was "old fashioned detective work," he said.

Lewis said the cold case unit opened the Mansion case hoping DNA evidence would lead them to a suspect. When that tack was unsuccessful, Lewis said detectives started using tools such as social media and uncovered new leads that took detectives to Illinois, South Dakota, and Pennsylvania, ultimately pointing them toward Salmon.

"Newer technology still played a vital role," he said.

With assistance from from the Shaler Township Police, Allegheny County Police, and Allegheny County District Attorney's Office, Santa Monica detectives and members of the Los Angeles District Attorney's Office travelled to Pittsburgh two weeks ago to arrest Salmon.