MANAGUA, Nicaragua -- 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. Sandinista Party's Radio Ya and other local media were reporting it appeared to be a suicide.

Alexis Arguello was found dead Wednesday at 57. He is pictured in June 1981 after beating Jim Watt to win the WBC lightweight title. Getty Images

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 and 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," Pryor told The Associated Press. "Those were great fights we had. This was a great champion."

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

Hundreds of people lined up to say goodbye to Arguello Wednesday night at a memorial service at the Palace of Culture in the capital of Nicaragua.

Student Jose Jarquin, 18, said "he was an example for everyone as a disciplined athlete, nothing like other boxers who have embarrassed us with their performances outside the ring."

Nicaragua President Daniel Ortega canceled a trip to Panama for the inauguration of President-elect Ricardo Martinelli and attended the service. Ortega described Arguello as "an extraordinary human being full of truth."

In 1999, a panel of experts assembled by the AP voted Arguello the best junior lightweight and sixth-best lightweight of the 20th century. Arguello never lost a fight at 130 pounds.

His popularity in his own country was so great that he carried the flag for Nicaragua at the 2008 Beijing Olympics, and led to his decision to seek public office.

"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 AP. "He was a ring tactician. Every move was thought out. And he was a wonderful, wonderful person."

Arguello turned professional in 1968 and lost his first bout. He didn't lose much after that, and six years later rallied to knock out Olivares in the 13th round and win the featherweight title.

Arguello went on to win the super featherweight and lightweight titles, his 5-foot-10 frame and long reach 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.

"I felt sad receiving the news and still find it hard to believe," retired boxer Oscar De La Hoya said from Los Angeles. "Alexis was my idol. When I was young, I heard so much about him and his fights and loved his style in the ring. In my opinion he was of the biggest and most influential fighters boxing has ever produced."

De La Hoya said Arguello attended his fight against Steve Forbes in May 2008, which was De La Hoya's last victory.

"We shared some great moments together before and after the fight," he said. "Arguello was definitely a legend in the boxing world because of all the joy he brought to his fans with his unforgettable career and amazing personality."

Arguello moved up in weight again in November 1982 to challenge Pryor for the 140-pound belt, a fight billed as "Battle of the Champions," and tried to become the first fighter to win titles in four divisions. More than 23,000 fans packed the Orange Bowl in Miami, and the two waged an epic battle in which Pryor knocked out Arguello in the 14th round.