A paediatrician known for his research on near-death experiences with children was convicted of waterboarding the daughter of his companion by holding her head under a bathroom tap.
The jury in the US state of Delaware returned its verdict on Thursday against 60-year-old Melvin Morse.
Morse was charged with three felonies - two for alleged waterboarding and one for alleged suffocation by hand. He was convicted of one felony - waterboarding in the bathtub, and five misdemeanours. Jurors reduced the second waterboarding charge to a misdemeanour and acquitted Morse of the suffocation charge.
Morse was ordered to surrender his passport and will remain out on bail until his sentencing, set for April 11. His attorney said he intended to appeal.
The girl and her mother testified that Morse used waterboarding as a threat or a form of punishment.
Waterboarding has been used in the past by US interrogators on terror suspects to simulate drowning. Many critics consider it torture.
Defence attorneys argued that "waterboarding" was a term jokingly used to describe hair washing the girl did not like.
But the prosecutor portrayed Morse as a brutal and domineering "lord and master" of his household, abusing the girl for years while her mother acquiesced in silence.