The Stroudsburg Pocono Record reports a jury on Friday found Michael Parrish guilty of first-degree murder.
The defense contends Parrish killed Victoria Adams and their son, Sidney, in the heat of the moment in July 2009. Prosecutors say the shootings were premeditated.
Authorities say Parrish, then a Monroe County Correctional Facility guard, shot Adams and their child several times before fleeing to New Hampshire. He was captured the next day.
Defense attorney Wieslaw Niemoczynski has described his client as "fundamentally insecure" and says he thought Adams was cheating on him.
Parrish could be sentenced to death or life in prison. The penalty phase begins Monday.
Information from: Pocono Record, http://www.poconorecord.com/