Brody was a journeyman, as in he'd go around the world, never staying in the same place for very long at all so he didn't wear out his welcome. One of his big places was Puerto Rico where he allegedly was thinking about buying into the company. Carlos Colon (Carlito and Primo's dad) owned the company and had a friend named Jose Gonzalez, more commonly known as Invader #1.
One night Gonzalez asked Brody to go into the shower to discuss business. Just about every wrestler in the locker room that night says that Gonzalez had a towel with a knife under it. Tony Atlas was in the shower and allegedly saw the whole thing. For some reason he wouldn't testify at the trial. Since there were no witnesses, Gonzalez claimed self-defense and was acquitted. All of that is pretty much the universally accepted story.
Now depending on who you want to believe, there were some very shady issues with this, such as the police/paramedics not being called for over an hour, subpoenas not being sent out until after the trial ended, and a pair of "security guards" coming into the operating room and telling the doctor to stop operating on Brody. I'm not sure I believe most of that aspect of it though.