This is short and sharp, I have proved it is Brett Partridge.

If you pause the red john murder scene when RJ slits her throat on the episode "His red right hand" when Jane said he makes a mistake, you can clearly identify that red john is Brett Partridge in the black hoodie. I have paused it on the right frame but I can't seem to be able to upload a photo on here. That's a shame, any suggestions on how I can share it?