Mona's hard drive may not be the key to the Pretty Little Liars mystery.

'Pretty Little Liars' Viewers Can Uncover 'A' By Season 5 Finale, Marlene King Teases Reveal

Of all the gigabits of information stored on the deceased teen's laptop, the reason for her death - and any information linked to 'A' - might not be among them.

"I'll tell you that right now, they're fixated on what's on the computer, but the mystery might be the computer itself," executive producer Joseph Daugherty teased, according to The Hollywood Reporter.

Will Alison Be Killed Off On 'Pretty Little Liars'? Marlene King Talks New Prison Storyline

Unfortunately for Caleb (Tyler Blackburn) and Spencer (Troian Bellisario), simply locating Mona's (Janel Parrish) laptop will be hard enough. As the search continues in "Over a Barrel," the two investigators will realize that hacking Ms. Vanderwaal's password will probably be easier than keeping their search within Toby-approved parameters.

Rosewood's newest cop is far from the straightest arrow on the force, but the Liars often go to criminal lengths that any other officer would balk at. Wherever Caleb and Spencer's search may lead them, it will end somewhere Toby (Keegan Allen) doesn't want them to go. Not that any of the Liars are particularly good at listening to advice they don't like...

Find out more when Pretty Little Lairs airs Tuesdays at 8 p.m. ET on ABC Family.

Tags: pretty little liars television ABC Family