Brett Partridge is not dead, in fact he was the first to "die". He is also Red John. He is the only member of Tyger Tyger to remove his tattoo, post mortem or otherwise. A forensics expert is not going to leave a trace or a tattoo, that means his apparent body, also.

I'm glad it is him, from the first episode of the first season and subsequent scenes and seasons after. Although his profession and demeanour was creepy, his final scene prior to his staged death was a complete u-turn from his usual cocky, cretinous behaviour. His character is the embodiment of the tyer, burning bright right in front of us, hiding in plain sight. 

Bravo, Brett. I hope he reveals something even worse than cop conspiracy and a victim list.