The parents of a gunman who shot and killed a state trooper engaged in “psychological manipulation” of their son and should be held responsible for the deadly ambush at a state police barracks, according to a lawsuit filed by the trooper’s widow.

Eugene Michael and Deborah Frein manipulated their son, Eric Frein, into “developing a strong dislike for police and acting on that dislike,” said the wrongful death suit, filed last week by Tiffany Dickson.

Eric Frein, now 34, was living with his parents in Canadensis when Cpl. Bryon Dickson, a 38-year-old Marine veteran, was fatally shot and Trooper Alex Douglass was permanently disabled in the Sept. 12, 2014 attack at the Blooming Grove barracks.

Frein, who eluded capture for 48 days, was convicted in April and received a death sentence.