GG has already admitted to being the last person to see her. According to him there are no other options. It was either an accident or he was responsible for her death. If it were an accident he certainly did everything wrong in terms of responsibility. Drinking, sleeping pills, going into the water at sunset, snorkeling with your sneakers on. Witnesses who said they just walked along the beach area for 20 minutes then got in the car and left only to return shortly before he reports her missing. That eliminates any other possibility if GG sticks to his story.
GG claims RG drowned and that is probably what happened it's just a matter of whether it was deliberate or an act of irresponsibility on his part. He knew they were drinking. He knew she had taken sleeping pills (whether on her own or he put something in her drink). He drove to that location twice at an hour of the day that was dangerous to go into the water when there were far safer places to snorkel on the island. He picked a site to say they entered the water full of sharp, jagged rocks which is almost impossible to walk on without shoes and/or without falling. His story has giant holes in them. jmo