Pretty Little Liars is so filled with murder, mayhem, and mystery, that it's easy to forget exactly what we don't know.
 
One mystery that's lingered for a while is who killed Ian Thomas (Ryan Merriman) during Season 2. We've always assumed it was a member of the "A" team, since his fake suicide note was planted by "A", but that doesn't tell us who on the "A" team has Ian's blood on his or her hands. And hey, maybe it wasn't actually the "A" team. You can never be sure on this show.
 
Will we ever find out the truth?

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PLL showrunner Marlene King says "yes," we will eventually learn the identity of Ian's killer. Though the "when" of that is still anyone's guess...

Find more Pretty Little Liars spoilers here.

Catch the next episode of Pretty Little Liars on Tuesday, February 12, 2013 at 8 p.m. ET/PT on ABC Family.

Source: @imarleneking