2 Women Were Killed on a Beach Vacation in 1973. A DNA Test Just Led to an Arrest.

In the nearly 30 years that Ernest J. Broadnax has lived in New York City, he has always been known for getting into trouble, with 14 arrests on charges like assault and burglary. He served three stints in state prison. But now, in an advanced age, he’s become known to neighbors as a cordial, but distant man, who has struggled with alcohol and drug addiction.

But none of the crimes in New York that he was charged with were as severe as the gruesome killings he is now accused of having committed. This week, the police in Queens arrested Mr. Broadnax for the 1973 murders of two women who had been vacationing in Virginia, the police there said.

A cold-case squad in Virginia Beach identified Mr. Broadnax, who is in his 80s, as a suspect by using technology that did not even exist when the women, Lynn Seethaler and Janice Pietropola, both 19, were killed inside a motel cottage near the oceanfront.

DNA evidence found at the crime scene was used last fall to match Mr. Broadnax’s profile in a national database, a Virginia Beach law enforcement official said. The official did not say what type of DNA was collected from the scene, and requested anonymity to discuss the pending case because doing so is illegal under Virginia law.

Mr. Broadnax, a native of Virginia, was arrested on Monday on a fugitive warrant issued by the Virginia Beach police. Officials there said he is charged with two counts of murder and one count of rape. He is being held on a New York City jail barge awaiting extradition, according to the police and jail records.

“Our objective now is to be able to bring justice for the victims, and for their families to be able to have a sense of peace and closure,” said Officer Linda Kuehn, a spokeswoman for the Virginia Beach police.

Ms. Seethaler and Ms. Pietropola were from Pittsburgh, Pa., and were on vacation when their bodies were found in an oceanside motel on June 30, 1973, according to the local police’s online summary of the case.

William Haden, the retired detective who handled the case, said in an interview on Tuesday that the killer strangled Ms. Seethaler, slashed her throat and shot her twice in the head; Ms. Pietropola was strangled, raped and shot three times, he said.

The police said the attacker had removed a screen and climbed into the room, according to The Virginian-Pilot. Investigators interviewed two men who had dated the women, The Pittsburgh Post-Gazette reported, but released them without charges. They were among hundreds of people questioned and thousands of leads exhausted by 1988, the police told The Virginian-Pilot. But the case went cold.

“I am just relieved,” he said. “It was an albatross around my neck all those years, and that albatross has now been removed.”

The arrest stunned Adedayo Peterson, whose mother was briefly married to Mr. Broadnax in the 1970s. She said Mr. Broadnax had served in the Army and had been incarcerated in Virginia before he met her mother. “I didn’t expect nothing like that,” Ms. Peterson said. “But I wouldn’t put it past him.”

The marriage, his second, was short-lived and soured after Mr. Broadnax became violent. He once whipped her mother with a belt and on another occasion pulled a gun on her brother, Ms. Peterson said.

A public defense lawyer assigned to Mr. Broadnax’s case could not be reached for comment.

A local television station, WTKR, reported in 2011 that the killings of Ms. Seethaler and Ms. Pietropola were two of at least 12 women with similar physical traits who were murdered or went missing in Virginia Beach between 1973 and 1985.

Though the police considered the possibility of a serial killer, investigators were unable to determine if the killings were connected, Mr. Haden said. Some of the women were killed in their homes and two were found floating in the ocean. Several other women vanished from the oceanfront and have never been found.

“Of course you look at that,” Mr. Haden said of trying to connect the killings. “You wouldn’t be worth the powder on your shoes if you didn’t.”

Mr. Broadnax has lived in New York since at least 1990, where he has been incarcerated three times for crimes including assault, according to corrections records. State law required him to submit DNA because he was convicted of a felony.

He was released from prison on parole in 2013, after serving most of an eight-year sentence for assault, according to state prison records. In that incident, the police said he was selling metal scraps in Manhattan in 2006 when he got into a fight with a customer and broke the man’s arm.

He settled into a first-floor apartment in Hollis, Queens, where neighbors said he was quiet but cordial, waving hello to neighbors, and carrying on small talk.

“He was one of the older people in the building,” said one neighbor, who also refused to give their name. “Sometimes he forgot things, like he had dementia. We all looked out for him, you know?”

A few months ago, Patrick Penafiel, 63, said, that he saw three detectives in the hallway, questioning Mr. Broadnax before searching his apartment. Mr. Penafiel only recalled one occasion when Mr. Broadnax socialized, when he was invited to a tenants’ meeting.

“He told us he was a recovering alcoholic, and drug addict,” he said. “He showed us his diploma from a rehabilitation center. We all clapped for him.”