Mark Fuhrman was right. The detectives weren't running the show.
I would bet anything that there was at least one brave detective fighting the tide, trying to tell everyone in the task force after reading the letters that the killer is most likely a black five percenter, whose very motto is "I am God" -- especially with the other rap lyric references. Their ideas are also steeped with occult numerology and esoteric and masonic influences, so tarot cards even fit with this profile since they originated with 14th century Muslims in Egypt and are favored by those in secret societies who pursue hidden knowledge.
One FReeper even nailed early on that the "Mr Policeman" was Carribean flavored English so I'm sure that wasn't lost on the detectives.