BOZEMAN, Mont. (AP) — A Montana man who pleaded guilty to stabbing his 72-year-old father to death has been sentenced to 50 years in prison.

The Bozeman Daily Chronicle reports Tanner Franks was sentenced Monday for the November 2017 death of William “Bill” Franks. The younger Franks pleaded guilty to felony mitigated deliberate homicide.

He said in court that his father was “controlling, manipulative and, at times, very physically abusive” to him and his family.

But Tanner Franks’ aunt and brother testified he was lying about his father living a “double life.” They said the elder Franks helped the community through his work at Bozeman High School, where he spent more than three decades as a teacher and administrator before retiring as associate principal in 2007.

Tanner Franks declined to speak during Monday’s sentencing.

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