Since the beginning I have doubts about the alleged explanation of Gatti's death. It seems unlikely that he committed suicide or that Amanada strangled him. Both explanations are absurd and facts hinder that explanation. Especially if we take into consideration the fact that there was a wound in the back of his head.
This morning, reading a Brazilian newspaper, I found an article on that case (which is still unsolved for me). Here's an excerpt of that article with my translation
De acordo com o laudo da polícia, antes de cometer o suicídio, Arturo Gatti se envolveu numa briga com a mulher, Amanda Carine, confusão testemunhada por cerca de 60 pessoas. “Eles brigaram na rua. Tanto é que ele a espancou violentamente e arrastou ela por um bom pedaço da rodovia puxando pelos cabelos”, disse o delegado Paulo Alberes.
Arturo teria agredido também um vigia, que chegou a perder os sentidos, ao tentar ajudar a mulher. Algumas pessoas que viram a cena ficaram revoltadas e chegaram a agredi-lo jogando pedras e até uma bicicleta, foi quando ele ficou ferido na cabeça.
TRANSLATION
According to the police statement, before committing suicide, Arturo Gatti had a fight with his wife, Amanda Carine, a disturbance that was witnessed by approximately 60 people. «They fought in the street. The fact is that he spanked her and dragged her on a good distance on the road pulling her by her hair», said the police chief Paulo Alberes.
Arturo had also attacked a guard, which eventually passed out, in tempting to help the woman. Several people who witnessed the scene were upset and started to attack him by hurling stones, and even a bicycle, at him. It is at this moment that his head was hurt. (My emphasis)
It's the first time that I see that (pseudo)explanation. I don't know if it makes sense. One thing is sure, it could explain why there was a wound in the back of his head.