A gunman in western Pennsylvania shot two police officers -- killing one of them -- in an early morning ambush-style attack, state police said.

The shooting happened in the town of Canonsburg, about 18 miles southwest of Pittsburgh, after the officers responded to a call about a domestic incident at 3:14 a.m. The officers were ambushed upon arrival "as soon as they approached the front of the residence," a Pennsylvania State Police spokesperson said at a press conference this morning.

The injured officers were transported to local hospitals, and one of them has since died, according to state police. Their names have not been released.

After a six-hour manhunt, police found suspect Michael Cwiklinski and a pregnant woman dead inside a second home, just a half of a mile away from where the two officers were attacked, the Pittsburgh Post-Gazette reported.

Authorities told ABC News there was an "active PFA" or protection from abuse order at the residence where the officers were dispatched.