Try to very much get these tirades recorded ,poss on a mobile phone ...I suggest all complaints mad to your manager should be by email with a read receipt..I have seen a situation akin to this in the past be when the complaint went higher up the chain the bully denied ever doing it and the manager (rsole) the guy gave the letters to said "what letters" and he left the company out of disgust....record and document everything possible as this will be support for a later date.