Season 2 Episode 20 episode 20

Pretty Little Liars Season 2 Episode 20 "CTRL:A" Promo

Pretty Little Liars Season 2 Episode 20 "CTRL:A" Promo

Here is the promo for Pretty Little Liars, Season 2 episode 20, titled: "CTRL:A". What are the police looking for on Caleb's computer and better yet, would could "A" have possibly planted on the computer to interest the police this much?