Santa Monica police have arrested a 53-year-old man in Pennsylvania in connection with the fatal shooting of a teenager in Santa Monica more than three decades ago.

Patrick David Salmon, who is suspected in the murder of 16-year-old Joaquin Mansion in the 700 block of Marine Street in Santa Monica on May 21, 1980, was arrested May 17 at his home in Shaler Township, a suburb of Pittsburgh.

Santa Monica police detectives and members of the Los Angeles County District Attorney’s Office made the arrest, along with Shaler Township police, Allegheny County police and the Allegheny County District Attorney’s Office. Evidence allegedly identifying Salmon as the gunman in the 1980 homicide was located at the home and he was taken into custody, Santa Monica police Sgt. Richard Lewis said.

Salmon is currently being held in Allegheny County Jail awaiting extradition to Santa Monica.

With the arrest, Santa Monica police believe they have solved one of the oldest cold cases at the department, said Det. Larry Nicols, one of two detectives who worked on the investigation.

“It’s fantastic; it’s the highlight of someone’s career,” Nicols said of making an arrest in a cold case that has spanned over 30 years.

Nicols said Mansion was killed in a poorly operated home invasion robbery. Police believe Salmon allegedly entered the home, demanded money from several people inside and when he didn’t receive it, he allegedly shot Mansion – who was the closest to the door – in the head, Nicols said. Mansion was a Los Angeles resident.

Salmon allegedly believed the home was a place for drugs and money, but Nicols said that “couldn’t be further from the truth,” noting that the youths inside were just hanging out and watching TV. Two juvenile co-conspirators had waited in a getaway car while Salmon, an adult at the time, was allegedly inside the house, Nicols said.

The two juvenile co-conspirators were located, arrested and convicted of the robbery and homicide in the months following Mansion’s death. But the alleged gunman, a transient who had been travelling through Santa Monica and was known to acquaintances only by a nickname, was never identified, police said.

The investigation was ultimately suspended for nearly 30 years until it was reopened by the SMPD Cold Case Unit on July 1, 2010.

Lewis noted that unlike many current cold case investigations, the Mansion homicide was not solved with the use of DNA evidence but rather “outstanding old-fashioned police work.” The lack of DNA evidence made the case more difficult and time-consuming, but detectives also took advantage of improved electronic law enforcement and open source databases that were not available in 1980, Nicols said.

Detectives were able to gather valuable leads and information that took them to Illinois, South Dakota and Pennsylvania in pursuit of the suspect, Lewis said.

“It just takes a lot of patience, a lot of frustration and a lot of miles – a lot of sky miles. We did quite a bit of travelling,” Nicols said of the work involved without the use of DNA.

“A lot of the difficulty was trying to find the witnesses because they had moved out of state and we had to travel and reinterview them.”

A key break in the case was a booking photograph obtained from the Santa Barbara Police Department when Salmon was arrested for aggressive panhandling in 1984, Nicols said. It was the closest booking photo police could find to the suspect’s description, he added.

Nicols said it was “absolutely satisfying” to make an arrest after so much time had passed and to be able to tell the news to Mansion’s family, with whom detectives had remained in touch throughout the investigation.

“They were as happy as they could be; they’re still going through the loss of their 16-year-old son and brother,” he said. “It was definitely closure for them.”

Lewis praised the dedication of the detectives toward the investigation that resulted in the arrest and said the department is proud to provide some closure for the victim’s family.

“It was an outstanding turn of events for this on many things,” he said of the case. “The department is happy that we can provide a conclusion to the cold case homicide and provide some gratification to the family of the victim.”