C'mon, this one's a no-brainer. Jenna has been sketchy from the very start, and we haven't seen her for a while. If anyone was going to join forces with "A" and stage a takedown, it would be her.
Some viewers and hardcore fans have noticed that Red Coat's first appearance happens around the time Jenna gets her sight back. Same with when she loses it. Could the two incidents be coincidence? Or a telling detail?
Jenna has been gone for a while (just like a few other suspects on this list). This would give her plenty of time to go undercover and wreak some havoc.
Why She's Not Red Coat:
The last time we see Jenna, she's still blind. And Red Coat, who is last spotted driving "A" around, obviously has sight. Unless Jenna has her sight back again, she's out.
Jenna's been hurt time and time again at the hands of "A," so we have a hard time believing the two would be in cahoots.