Almost 35 years ago, two unarmed U.S. sailors were killed in a terrorist ambush in Puerto Rico. Decades later, their killers may finally be brought to justice.

Puerto Rico authorities say the recent sentencing of a man that played a minor role in the attack, which the group known as Los Macheteros staged in reaction to the death of an activist in a U.S. prison., could finally unravel the long-unresolved case from a violent phase of Puerto Rico's national movement.

Juan Galloza Acevedo, 78, was sentenced in May after police investigating the 1979 incident showed up at his quiet retirement community to question him about his role in the attack.

"He obviously didn't expect to see us," said Special Agent Tim Quick of the Naval Criminal Investigative Service (NCIS).

NCIS officials say they will be back in the U.S. territory soon to work with local authorities in hopes of surprising some more militants.

"We see potential for additional arrests," Quick said.

Galloza, who was sentenced May 8 to five years in prison, played a minor role in the ambush. Attackers fired assault rifles and a machine gun at a bus carrying 17 sailors from a Navy base at Sabana Seca, a coastal area several miles from the house where Galloza was living when authorities found him in 2006.

At one point, 13 people were suspected of involvement. Four of those have since died, including one suspected gunman who authorities say died in a drug-related shooting.

NCIS officials declined to provide further details on the hunt because the investigation might be jeopardized.

Federal authorities reopened the case after the Sept. 11 terror attack on the U.S. revived Washington's interest in suspected terrorists. Still, as the investigation dragged on, many people questioned whether it was worth the time and money, said Lou Eliopulos, director of NCIS's Office of Forensic Support.

"It was an incredible task to try to put it together," he said, adding that agents were lucky a retired Puerto Rico police detective had preserved the evidence. "We were faced with individuals who asked why we were doing this, that we would never make it to the courtroom."

Galloza is one of those wondering why authorities are still pursuing suspects.

"God imparts justice," he said in a brief phone interview with the Associated Press from the Metropolitan Detention Center in New York City. "What do people gain from catching someone else and making them pay for something after so many years?"

A widow of one of the sailors killed in the attack has a different view. Patty Ball acknowledged that Galloza expressed remorse and apologized to the families of victims at his sentencing hearing in New York, but said that wasn't enough.

"This was not about forgiveness. This was about justice and responsibility," she said in a phone interview. "I think that people need to be held responsible for their actions. I don't care how old a case this is."

She was living in Puerto Rico with her husband, Petty Officer John Ball, and their two children as part of his three-year assignment when the attack occurred. She moved her family back home to Wisconsin the next day.

Galloza became a supporter of Los Macheteros around 1969 but didn't become active until about 1978, according to court documents. Three weeks after the attack, Galloza left the group because of his objections to its tactics and later found a job in a purse factory, officials said.

The group, which is listed by the U.S. government as a terrorist organization, claimed responsibility for killings, bombings and robberies in the 1970s and '80s, including a $7 million holdup of a Wells Fargo depot in 1983. Its visibility diminished after a flurry of arrests in 1985.

Galloza says he didn't know authorities were looking for him. "The only thing I said was, 'If I made a mistake, I will pay for it,'" he said. "I want to make things right."

Recently put in a prison hospital in Massachusetts for treatment of heart problems, Galloza would like to be transferred to Puerto Rico because of his health troubles, which also include rheumatoid arthritis and diabetes.

"They sentenced me to die," he said. "They knew I was not going to last five years. I'm more dead than alive."

Based on reporting by The Associated Press.

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