NORRISTOWN, Pa. (AP) — A man is facing life in prison without possibility of parole after being convicted of killing his 16-year-old girlfriend in a southeastern Pennsylvania alley last year.

Jurors in Montgomery County deliberated for about three hours before convicting 20-year-old Brandon Pierce of Norristown of first-degree murder and other charges in the July 2011 death of Dominique Devlin.

Investigators said they believe he lured her into an alley and shot her to death in retaliation for alleged involvement in setting him up to be robbed a few weeks earlier.

The (Norristown) Times Herald says the defendant stood stone-faced Wednesday as the verdict was announced while his relatives cried behind him.

Pierce faces a mandatory life term when he is sentenced in February.

(© Copyright 2012 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)

Top Content On CBSPhilly

Watch & Listen LIVE