When a scuba diver brought Mary Jo Kopechne’s body up from the mostly submerged car by the bridge on Chappaquiddick Island, Edgartown Police Chief Dominick J. Arena cradled her for a moment.
“I was sitting and I put my arms around her and pulled her up,” he would later testify.
Mr. Arena, who was 89 when he died March 3, didn’t know Kopechne’s name as he sat there that morning wearing swimming trunks he had borrowed from a nearby residence.
And he wouldn’t learn until later that day, on July 19, 1969, that she had been a passenger in a car driven by Senator Edward M. Kennedy that had gone off the Dyke Bridge shortly before midnight, turning and landing top-down in the water.
Before the diver arrived, Mr. Arena himself had plunged repeatedly into the water to see if anyone was still in the car. “There was a strong current and it exhausted me,” he told reporters later, “and I think I’m a pretty good swimmer.”
The events on Martha’s Vineyard that day and in the weeks that followed became a significant chapter for the storied Kennedy family — the tragedy many historians believe prevented Ted Kennedy from becoming president.
Because Mr. Arena was the first law enforcement officer on the scene, and the key investigator, those weeks and months would also come to define his career.
He knew he’d always be remembered as “the Chappaquiddick chief.” Mr. Arena arrested Kennedy, who days later pleaded guilty to leaving the scene of an accident.
And though every decision made by everyone involved in the investigation and court case would be dissected in articles and books, Mr. Arena would always call the death of Kopechne “an accident, a true accident caused by natural conditions.”
Kopechne, a campaign worker for the 1968 presidential campaign of US Senator Robert F. Kennedy, had been attending a party at a cottage on Chappaquiddick Island with Edward Kennedy and others before he offered to drive her to the ferry back to Edgartown.
Hours after her body was pulled from the car, Mr. Arena told reporters: “I am firmly convinced that there’s no negligence involved, but the matter of the time period after the accident — there is in my eyes a violation concerning going from the scene, leaving the scene.”
If Kennedy “sat in his house for five minutes without reporting the accident,” Arena added, “he is in violation of the law.”
The scrutiny Mr. Arena faced was unrelenting. Reporters arrived from across the country and from Europe. Chappaquiddick, the Globe noted in 1980, “catapulted him into the news as the most photographed and widely quoted small town police chief in the country.”
Looking back in 1991, he recalled that “you have the outside world looking at you every day, because it’s the Kennedys. We had a six-person office and I was the guy who was supposed to be investigating, talking to people, talking to the press. It was just a monumental task.”
To accommodate reporters and TV crews, Mr. Arena gave media briefings twice a day, usually in the parish hall of a local church.
“I really honestly felt that by trying to make known everything we had short of jeopardizing our case, I showed we were doing the best we could,” he said in 1991.
At the time, news reports described him as affable and helpful. Mr. Arena, the Globe reported, “was highly respected by newsmen because of his candor and his willingness to cooperate with out-of-town reporters, qualities not always easy to find among small town police chiefs.”
Needless to say, he couldn’t have anticipated being part of an international news story when he was hired two years earlier.
He was 37 when he became Edgartown’s police chief in 1967, after nearly 13 years with the Massachusetts State Police that included a stint at the end as an investigator in the office of Massachusetts Attorney General Elliot Richardson. Mr. Arena had joined the State Police after serving as a staff sergeant in the Marine Corps and was assigned to the State House in 1964.
He spotted the Edgartown police chief job in a newspaper advertisement and was chosen from among three candidates, the Globe reported. During his first year, he spent much of his free time readying a Vineyard cottage for the arrival of his soon-to-be wife, Yvonne.
Chappaquiddick “changed my life . . . in that I will forever be connected with it,” Mr. Arena told the Globe in 1975. By then he had left the Vineyard to become the police chief in Essex Junction, Vt., where “our biggest problem here involves traffic control.”
More than six years after Kopechne’s death, he added, “I still get a call from a major news service about once a week.”
The oldest of seven children, Dominick James Arena was born in Norwood on Nov. 18, 1929. The family of his father, John Arena, had emigrated from Italy. His mother, Mary Dorigan, was an Irish immigrant from County Leitrim.
Mr. Arena grew up in Walpole, where he graduated from high school and was a standout athlete in football and basketball.
“He was 6-foot-4 and 220 pounds most of his life,” said his daughter Julie Locke of Hudson. “He was always larger than life.”
Known as Jim or Jimmy to family and anyone who knew him well, Mr. Arena enlisted in the Marine Corps after high school and served from 1948 through 1952, including during the Korean War. Returning to Massachusetts, he graduated from Dean Junior College with an associate’s degree and became a state trooper.
One evening some years later, he was at The Lord Fox in Foxborough, where he met Yvonne Barber.
“She had been singing at the piano bar and there was a man who was starting to get rowdy, so my father stepped in and asked him to leave,” Julie said. “Mom and Dad locked eyes, and that was it.”
They married in August 1968 and lived at first in Edgartown. After his stint in Essex Junction, Mr. Arena also served as police chief and fire chief in Lincoln. He also had lived in Acton and, at the end, in Hudson. After retiring from law enforcement, he was chief security officer at the US District Court in Worcester until stepping down at 82. Mrs. Arena died in 2016.
“First and foremost, he was a family man,” Julie said. “He loved his job, but he definitely was wonderful about separating the two. He had a real knack for loving what he did and leaving it at the door when he came home. Such a lesson in life: When you come home, it’s family time.”
A service has been held for Mr. Arena, who in addition to Julie leaves three other daughters, Wendy Santini of Easton, Pa., Christine of Burlington, Vt., and Deborah Coryer of Colchester, Vt.; three sisters, Ellen Farrell of Norwood, Ethel Fenstermacher of Marlborough, and Joan Follett of East Walpole; 10 grandchildren; and a great-grandchild.
“There are people who say to me, ‘What effect did Chappaquiddick have on you?’ ” Mr. Arena mused during the 1991 Globe interview. “I say that I could become the chief of police of New York City and when I die, they’ll still say, ‘He’s the Chappaquiddick chief.’ ”Bryan Marquard can be reached at firstname.lastname@example.org.