MANAGUA, Nicaragua (AP) — Alexis Arguello, who fought in one of boxing’s most classic brawls and reigned supreme at 130 pounds, was found dead at his home early Wednesday.

Coroners were conducting an autopsy to determine the cause of death. Sandanista Party’s Radio Ya and other local media were reporting it appeared to be a suicide.

The La Prensa newspaper reported that Arguello — elected mayor of Nicaragua’s capital last year – was found with a gunshot wound to the chest.

The 57-year-old Arguello retired in 1995 with a record of 82-8 with 65 knockouts and was a champion in three weight divisions. He was perhaps best known for two thrilling battles with Aaron Pryor and fights with Ray Mancini, Bobby Chacon and Ruben Olivares.

“I’m kind of in a daze right now. I can’t believe what I’m hearing,” Pryor told The Associated Press. “Those were great fights we had. This was a great champion.”

Nicknamed “The Explosive Thin Man,” Arguello was inducted into the International Boxing Hall of Fame in 1992, where flags were flying at half-staff in his honor Wednesday.

In 1999, a panel of experts assembled by The AP voted Arguello the best junior lightweight and sixth-best lightweight of the 20th century. He never lost at 130 pounds, and his popularity in his own country was so great that he carried the flag for Nicaragua at the Beijing Olympics.

“Not only was he one of the greatest fighters I’ve ever seen, he was the most intelligent fighter,” Bob Arum, who promoted some of his biggest fights, told The Associated Press. “He was a ring tactician. Every move was thought out. And he was a wonderful, wonderful person.”

Arguello turned pro in 1968 and promptly lost his first bout. He didn’t lose much more, and six years later knocked out Olivares in the 13th round to win the featherweight title.

Arguello went on to win the super featherweight and lightweight titles, his 5-foot-10 frame allowing him to move up in weight without losing his tremendous punching power. At the time, he was only the sixth boxer to win championships in three weight classes, and was considered for a while the best pound-for-pound fighter in the world.

He moved up in weight again in November 1982 to challenge Pryor for the 140-pound belt, a match billed as “Battle of the Champions.” More than 23,000 fans packed the Orange Bowl in Miami, and the two waged an epic battle before Pryor knocked out Arguello in the 14th round.

“It was a brutal, brutal fight,” Arum said. “That was something I will never, ever forget as long as I live. That was one of the most memorable fights I ever did.”

The bout was named “Fight of the Year” and “Fight of the Decade” by Ring Magazine, but was shrouded by controversy. Pryor’s trainer, Panama Lewis, gave him a water bottle after the 13th round that many believe contained an illegal substance – an accusation Pryor denied.

A rematch was ordered and they met again a year later at Caesars Palace in Las Vegas. This time, Pryor knocked out Arguello in the 10th round.

“We always talk to each other about that first fight,” Pryor said. “I never went into the fight knowing I could beat Alexis, I just went into the fight to beat Alexis.”

Arguello announced after the fight that he would retire from boxing, but as so often happens in the sport, Arguello couldn’t stay away from the ring.

He returned to win two fights in 1985 and 1986, then didn’t step in the ring until 1994, when he made a brief comeback. He retired for good the following year.

“Alexis Arguello was a first-class fighter and a first-class gentleman,” said Hall of Fame executive director Edward Brophy. “The Hall of Fame joins the boxing community in mourning the loss of a great champion and friend.”

Arguello fought against the Sandinista government in the 1980s after it seized his property and bank account, but later joined the party and ran for mayor of the capital last November. He defeated Eduardo Montealegre, though opponents alleged the vote was fraudulent.

Arguello had returned Sunday from Puerto Rico, where he honored the late baseball Hall of Famer Roberto Clemente. His death prompted Nicaragua President Daniel Ortega to announced he was canceling a trip to Panama for the inauguration of President-elect Ricardo Martinelli.

“We are upset,” presidential spokeswoman Rosario Murillo said. “This is a heartbreaking announcement. He was the champion of the poor, an example of forgiveness and reconciliation.”