Credit: Troian Bellisario Instagram

In the last episode of Pretty Little Liars, Spencer’s (Troian Bellisario) parents told their pill-popping daughter that they couldn’t cover for her this time, leading us to ask the question: How did they cover for her last time? Here are our top theories!

She can’t remember Ali’s disappearance

The night of Alison’s disappearance, she wandered back into the sleepover with the other Liars in a somewhat confused state, explaining to her friends that she had left because she had heard Alison scream. Does she remember what happened while she was away from the sleepover? Because she looks like a total space cadet, and now that we know she can drive all the way to school and fall asleep in Ezra’s classroom with no memory of the event, we’re wondering what else she can do while in a drug-induced stupor. Can she remember the night of Alison’s disappearance? Do she and her parents think she was involved in Ali’s attempted murder? Was she?

She attacked Alison shortly before she disappeared

Another suspicious flashback that seems particularly relevant is the one that Mrs. Hastings remembers in Season 3, Episode 23. In it, Alison wanders back into the Hastings home late one night with a split lip. When Spencer’s mom asks Ali about it, she mumbles something about how girls can fight so much meaner than boys. Did Alison get into a fight with Spencer that night? It seems strange that they would have left the Hastings home to do so, or that Ali would feel comfortable returning afterwards, but we wouldn’t put it past the manipulative mean girl. Did the power struggles between these two besties finally come to fisticuffs? Is that what Ali’s smile at the end of this scene is about?

She was at Radley when Toby’s mother jumped

Everything leads back to Radley, amirite? Everyone is obsessed with that place, and we wonder if Spencer had a history with the mental health facility before she was a patient there in Season 3. If she somehow stole drugs from the facility — perhaps with Alison’s help — or was a patient there for a short period of time, it would connect her with a lot of the other lingering mysteries from that time in Pretty Little Liars’ past. Most pressingly: the death of Toby’s mother. We know that someone convinced Wilden to alter the police report of Marion Cavanaugh’s death, and we know that Mr. Hastings is desperate to shut Radley down once and for all. Might Spencer have somehow been involved with Toby’s mother’s death? Perhaps, she was even so messed up from her pill addiction that she doesn’t remember her own involvement? If executed poorly, this storylines could feel totally soap (in a bad way), but if done right, this reveal could have tragic and intriguing repercussions.

What do you think Spencer’s parents covered up for her back in the day? Share your theories in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, February 25, 2014 at 8 p.m. ET on ABC Family.

Kayti Burt is a contributing writer for Wetpaint Entertainment with a penchant for all things pop culture. Follow her on Twitter and Google+!