The reason why everyone assuming that he raped her is the mentioning of her boyfriend which driven him jealous and mad. It is clearly he chocked her to death. Think about it, if he really would raped her someone sooner or later would find her with traces of sperm, hair and saliva from him and he would already be in juvie. They had to hid her dead body Out of public and i guess he and his brother hid the her body in a drum container in the forest to let it rot. Maybe That's one of the reason why they making their videos in the forest to keep and eye no one would find it