Former Edgartown police chief Dominick Arena, who had earned fame — both in life and later in film ­— for his role as police chief during the infamous 1969 incident involving Sen. Edward M. Kennedy on Chappaquiddick, died on Monday in Westborough. He was 89 and had suffered from a long period of declining health.

Jim Arena, as he was known, had been on the job for two years when Ted Kennedy drove off the Dike Bridge on the night of July 18, 1969. Mary Jo Kopechne, who was a passenger in the car, died in the accident.

The news reverberated around the world and cast tiny Chappaquiddick — and sleepy Martha’s Vineyard — in the harsh glare of the national news spotlight for the first time in history, forever changing the Island.

Chief Arena was a member of the dive team that searched the waters of Poucha Pond the morning after the accident. He later arrested Senator Kennedy and charged him with leaving the scene of an accident, a decision that earned the chief criticism in some quarters. But Chief Arena defended the decision, saying he did not have enough evidence at the time for further charges.

Mr. Kennedy pleaded guilty to the charges.

Chief Arena took the job in Edgartown in May 1967 at the age of 37. His annual salary was $10,000.

He left in 1973 to take a job in Essex Junction, Vt. He later became chief in the town of Lincoln.

In an interview with the Gazette just before he left the Island, he was asked whether he would he do anything differently if he had the Kennedy case to handle again.

“I don’t know,” he replied. “If I had known about the party sooner . . . I saw Mr. Kennedy’s driver, Jack Crimmins, and one of the girls at the party, Cricket Keough, in the town hall corridor the morning after the car went off the bridge, and if I had known about the party I’d have gotten statements from them. But the party, whatever its interest to other people, had nothing to do with me. My job was to investigate an accident, and the record will show that I’m the only one who got a conviction.”

And to the suggestion that Dominick Arena was too nice a guy to be a cop, he replied: “I can be as tough as necessary. In my opinion a part of the job is to prevent situations that require toughness.”

The actor John Fiore played Chief Arena in the 2018 movie Chappaquiddick, a John Curran film that revisited and retold the story of the incident.

Chief Arena’s law enforcement career had spanned many decades including more than a decade as a state police trooper who did investigative work for the criminal division of the Massachusetts Attorney General’s office. Originally from Walpole, he served four years in the U.S. Marine Corps.

The Edgartown police department this week posted an appreciation on the department Facebook page.

“We send the Arena family our heartfelt condolences. Chief Arena will be missed by many, and we thank him for his service to Edgartown,” it said.

Funeral services will be held on Saturday in Hudson.