Rep. Mark Critz came from behind to defeat his Democratic colleague, Rep. Jason Altmire, in Pennsylvania’s redrawn 12th district tonight.

Altmire called to concede to Critz, according to a Critz spokesman.

Democrats initially viewed the redrawn 12th district as favorable to Altmire because it included more than 60 percent of his current territory plus his hometown area. But in the low-turnout race, Critz’s support from organized labor proved pivotal, especially in his base of Johnstown.

The race became increasingly competitive in the final weeks, and both Members emptied their bank accounts for the primary. Critz, a former top aide to the late Rep. John Murtha (D-Pa.), spent $100,000 of his own money to boost his bid.

Tonight, that looked like money well spent. Critz defeated Altmire by a slim 4-point margin with 94 percent of precincts reporting, according to the Associated Press.

This November, Critz faces attorney Keith Rothfus, the newly minted GOP nominee, in the competitive district surrounding the north Pittsburgh suburbs.