Melvin Morse, 60, was found guilty by a Sussex County Superior Court jury of nine women and three men, the Cape Gazette in Lewes reported.
The girl, now 12, testified against her stepfather, saying he abused her with waterboarding, suffocation and other harsh punishments for misbehaving. She said in court Monday she pretended to die once when Morse held her nose and mouth shut.
"I thought since he was pretty much trying to kill me, I pretended to play dead," said the girl, who ran away from her Harbeson-area home in July 2012 at age 11. "I couldn't really stand up anymore. I felt if I didn't do something about it, I would die.
"Sometimes I thought I heard him yell, 'Die,'" she said of the alleged waterboarding. "One time I tried to tell him it hurt. He didn't listen to me. I don't think he even heard me."
Morse, who is married to and has a biological child with the girl's mother, was charged with abuse and reckless endangerment. The girl's mother, Pauline Morse, pleaded guilty to lesser charges, admitting she did nothing to stop the abuse.
The defense painted Morse was a caring and attentive parent, the Gazette said.
The conclusion of the trial took an unexpected twist when defense attorney Kevin Tray fell ill during his spirited closing argument during which he tried to undermine the credibility of the 12-year-old victim's testimony.
While bailiffs attended to Tray, Morse could be heard whispering to unidentified spectators: "He's been working 18-hour days."
Co-defense attorney Joseph Hurley completed the final statement.