amy acker person of interest s3 'Person of Interest' Season 3: Amy Acker joins the cast full timeSeason 3 of “Person of Interest” will get a little more interesting with the addition of a full-time adversary for Finch and Reese.

Amy Acker (“Angel”), who has guest-starred in a handful of episodes of the CBS hit, is joining the cast full-time in the fall, CBS and Warner Bros. announced Saturday (July 20) at Comic-Con.

Her character, a hacker named Root, was hoping to track down the Machine in last season’s finale, but it had relocated by the time she, Finch (Michael Emerson) and Reese (Jim Caviezel) converged on its former location. The final shot of Root last season was of her in a mental hospital, receiving a call from the Machine.

Also Saturday, CBS and Warner Bros. announced a chance for fans of the show to have their photos featured as possible persons of interest in Season 3. Details will be available on the show’s Facebook page.

Acker is a Joss Whedon regular, having starred in “Much Ado About Nothing,” “The Cabin in the Woods.” and “Dollhouse” in addition to “Angel.” Her other credits include “Alias” and “Happy Town.”