About 1,000 people packed a Montreal church Monday morning to bid farewell to retired boxer Arturo "Thunder" Gatti, as rumours about the cause of his death continued to plague his family and friends.

During the service at Montreal's Notre Dame de la Defense church, those who knew him remembered a good friend and great boxer.

"It's a good guy that left us," said Victor Salvatore, a former Canadian lightweight champion who grew up with Gatti. "People who knew him know he was a good person."

Local reporter and family friend Jeremy Filosa said he wished he had been given the chance to say goodbye to his light-welterweight champion friend.

"I just wish I had one last chance to just give him a big, friendly hug and just tell him that we loved him so much," he told CTV Montreal on Monday.

Gatti spent his early years in Montreal, before moving to New Jersey to turn pro in 1991.

Montreal boxing promoter Yvon Michel called Gatti "the most successful boxer ever from Quebec."

Gatti ended his 16-year career in 2007 with a record of 40-9.

"I don't think we'll see another fighter like this," said boxing trainer Howard Grant. "You have to go back to the old days and guys like Rocky Graziano or Jake La Motta."

Boxing expert Russ Anber said Gatti's talent was apparent from an early age.

"The little boy that we saw grow up was such a marvel in the gym, watching him do things and imitate all types of fighters -- we were all amazed at watching this little kid do that," Anber told CTV Montreal.

At his service, Gatti's mother, Ida, was presented with her son's World Boxing Council championship belt by referee Gerry Bolen. She held the belt up in the air as she left the church.

And former heavyweight champion Mike Tyson sent a letter, telling the story of the first time he met Gatti, when the boxer was only nine-years-old.

"I was always happy to see his success," Tyson said. "I am happy to have been a part of his short, exciting life."

Gatti's service was read in three languages -- English, French and Italian -- with his family filling the first four rows in the church.

Gatti's unexpected death

Gatti, 37, was found dead on July 11 in the apartment that he and his wife, Amanda Rodrigues, were renting in the posh Brazilian seaside resort of Porto de Galinhas.

Brazilian media reported on the weekend that an autopsy on Gatti's body found that the former junior welterweight champion could have committed suicide, been accidentally killed, or murdered.

The media reports quoted the autopsy as saying Gatti was found "suspended and hanged, indicating he may have committed suicide."

However, murder or accidental death were not ruled out.

Outside the funeral, friends and family said they don't believe the jovial boxer would have taken his own life.

"It's impossible. Arturo would never, never, never kill himself, never," friend Victor Salvatore told CTV Montreal. "I would bet my life that Arturo would never kill himself. He loved life too much."

Local police have accused Rodrigues of strangling her husband with a purse strap while he slept, and produced a bloody knife that they said was found in the back of Gatti's head.

Investigators have also said the apartment door did not show signs of a forced entry, and that only keys belonging to Gatti and Rodrigues were used to enter the apartment.

Police have detained Rodrigues, but have yet to charge her with any crime. She has repeatedly denied any wrongdoing.

Police have until Wednesday to provide details of their investigation to prosecutors, who will make the decision on whether charges will be filed.

The couple's one-year-old son, Arturo, Jr., is currently in the care of Rodrigues' family.

With files from The Associated Press, The Canadian Press and CTV Montreal's Danielle Hamamdjian