"It is still too early to say anything concrete, although it is all very strange," Alves said. He declined to give more details.

A spokeswoman for the state public safety department said Gatti's wife and son were unhurt. The woman declined to give a name, in keeping with department policy.

"There were no bullet or stab wounds on his body, but police did find blood stains on the floor," she said.

Brazilian boxer and four-time world champion Acelino "Popo" Freitas told the G1 Web site of Brazil's largest TV network, Globo, that he was a close friend of Gatti and his wife, and that he "knew they were having some sort of problem and were about to separate."

Known for his straightforward punching and granite-like chin, Gatti captured the junior-welterweight title in 1995, when he defeated Tracy Harris Patterson in Atlantic City. His brawling style and natural charisma made him a fan favorite, and he became one of New Jersey's adopted sons while fighting some of his most memorable battles on the Boardwalk.

"I never saw a crowd show so much love for someone like the way that the crowds flocked to Arturo's fights in Atlantic City," said referee Randy Neumann, who officiated Gatti's last fight, against Alfonso Gomez two years ago. "I mean, they were so into him, and the crowds were electric. He just fought his heart out every fight."

Gatti continued to keep a home in Jersey City after he retired in 2007 with a career record of 40-9 and 31 knockouts.

"His entire boxing career, he fought with us; we've known him since he was 17," Kathy Duva of promoter Main Events told the Associated Press. "It's just an unspeakable tragedy. I can't even find words. It's a horror."

Gatti defended his title three times before moving up in weight and getting stopped by Angel Manfredy in 1997. He lost twice more before running off four consecutive wins, setting up a big payday against Oscar De La Hoya. He was knocked out in the fifth round of a lopsided fight.

The first time Gatti met Ward, in May 2002, the 140-pounders traded devastating blows for 10 rounds before Ward earned the split decision, by one point on one scorecard and two points on another.

In the rematch, Gatti earned a unanimous decision.

Gatti won the decision in their rubber match at Boardwalk Hall in June 2003.

Gatti attempted a comeback in July 2007, getting knocked out in seven rounds by Gomez. Afterward, he announced his retirement in the dressing room at Boardwalk Hall.