Police investigating the death of former Canadian boxing champion Arturo Gatti are working on the assumption his wife strangled him with her purse strap while he drunkenly slept.

While cautioning that nothing is being ruled out, lead investigator Moises Teixeira told The Associated Press on Monday he is certain the woman acted alone.

"It was technically impossible for a third person to have been in the flat," where the Montreal fighter was found dead early Saturday, Teixeira said. "The investigation isn't finished, but we continue to think she did this alone."

Brazilian authorities detained the wife, Amanda Rodrigues, 23, and formally accused her Sunday of killing Gatti at a posh seaside tourist resort in Brazil.  Prosecutors will later decide whether she'll be formally charged.

Rodrigues told investigators she awoke Saturday about 6 a.m. to find her husband's body in the apartment they rented in Porto de Galinhas, a seaside resort in northeastern Pernambuco state.

Rodrigues told police she had a fight with Gatti after dinner Friday night and he pushed her to the ground, resulting in minor injuries to her elbow and chin. Witnesses also reported to police the couple fought and that Gatti was drunk.

Rodrigues told police the 37-year-old former junior welterweight champion then got into a cab with their son and returned to their rented apartment, leaving her alone downtown.

Teixeira said witnesses told police Gatti left his son to sleep in the apartment, then returned to the city centre to find his wife. She arrived at the apartment before he did and waited for him. They then both went upstairs together.

Rodrigues told police she slept on the second floor of the apartment with her son, while Gatti slept on the first floor. She told police she awoke at 6 a.m. to feed her son and discovered her husband's body. Police say he most likely had been killed at least four hours before that.

Teixeira said police do not think anyone else entered the apartment and killed Gatti -- he said there were no signs of forced entry and electronic locks indicated nobody else had entered the room aside from Rodrigues and Gatti.

Signs of trouble?

Those who knew the couple say there were signs their was trouble in the relationship.

Montreal boxing promoter Yvon Michel says Gatti and Rodrigues both had wild personalities, and that led to problems.

"Everybody around him also knew that it was also a difficult relationship with his wife," said fight promoter Yvon Michel.

"He was a genuine person who was living on the fast track, and wanted people around him, the same kind of people, and I believe his wife was also a little bit wild too, so not a good mix."

In the spring, Gatti was charged with assaulting Rodrigues, but the charge was later resolved out of court.

"Thunder" mourned

Friends and fellow boxers were dismayed by the death of the man whose aggressive fighting style earned him the nickname "Thunder".

"It's very sad, it's... I've got goosebumps thinking about it," said Howard Grant. "It's very sickening this thing.

Grant, an Olympic boxer and gold medallist at the Commonwealth games, says Gatti was always entertaining in the ring.

"Arturo was a guy that was like a blood and guts guy. You know, he's losing, his eyes is shut, he's about to get knocked out and he throws one shot and he knocks the opponent out. And I think the kind of drama that he brought to boxing it hasn't been seen for a very, very long long time," said Grant.

- With files from ctvmontreal.ca -