I didn't explain my reasoning previously, the reason for the tall and dark black woman is because she is the opposite of everything that people describe red john to be. It is only obvious that it would be the opposite of what is described to be red john.

my theory is not up for debate, it is correct.

now some might say that he's a man because of his voice, this is not the case, simply because she has a gidget that changes and alters the voicing.

if you go to season 3 episode 5 and stop on exactly 15:32 min then u will see the black women AKA red john in the background engaging in a suspicious conversation.

in conclusion, I am right.