We’ve had our twin radar activated for some time now, despite insistences from the Pretty Little Liars Powers That Be that the twin storyline will not be explored. We call shenanigans! We totally think Alison had a twin and that she’s Red Coat. Here are five reasons why.

The Liars and Mrs DiLaurentis have seen “Ali”

Last episode gave us a chance to catch up with Mrs. DiLaurentis, who has understandably not been handling her daughter’s death well. In fact, she’s been seeing Ali everywhere. Mrs. D. claims to believe they are hallucinations, which is strange because if Ali did have a twin  obviously, Mrs. D. would know about it. Does Mrs. DiLaurentis know more than she’s letting on? Has she been seeing Ali’s twin, and potentially helping her? Is Mrs. D.’s grief just as much about how she has treated her other daughter, as it is about Ali’s death?

We’ve seen “Ali” as Red Coat

Not to overstate the point, but we’ve actually already seen someone who looks exactly like Ali as Red Coat. She pulled the Liars and Mona out of the Thornhill Lodge fire in the Season 3 finale. Mona claims that Red Coat wears Ali masks, but we know a real face when we see one. Was PLL using Sasha Pieterse in that scene to demonstrate what the Liars actually saw? Or was Sasha as Red Coat totally objective? If so, Red Coat has to be Ali’s twin.

The pictures/plaques on the DiLaurentis’ walls

All you have to do is visit the Tumblr “twin theory” page for some serious detective work regarding the clues around the DiLaurentis’ house. There are numerous framed photos that hint at DiLaurentis twins. How have the Liar never noticed this before?! Was Ali so much of a narcissist that they thought there was nothing strange about two portrait photos of Ali in one frame (one either side of Jason)? Probably. There’s also a decorative plaque hanging in Ali’s room in a flashback. It is in French, but according to one Tumblr user, reads: “This is the double laugh, the double smile, and double the trouble if you’re blessed with twins.”

Ali had a twin in the books

PLL the series does not follow PLL the book faithfully, but it has been known to take one or two ideas from its pages. One of the most important plot points of the book is that Ali had a twin, Courtney. Courtney was a patient at Radley, but managed to switch places with Ali. While she is pretending to be Ali, she becomes good friends with the Liars, but Ali eventually manages to break out of Radley and kills Courtney for taking her life. Could the television show be doing a twist on that plot? Could Ali’s twin still be alive, and masquerading as Red Coat?

Red Coat is living at the DiLaurentis house

We immediately found it telling that Red Coat is camping out at the DiLaurentis house. Sure, it’s often abandoned, but it is also smack dab in the middle of a residential neighborhood, which means it is highly visible. There’s no reason for Red Coat to hang out there unless she has some sort of sentimental connection to the property (and its sometimes inhabitants). If Red Coat is a DiLaurentis, this makes perfect sense.

Do you think Red Coat is Ali’s twin? Why or why not? Share your theories in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, August 20, 2013 at 8 p.m. ET/PT on ABC Family.