DETROIT -

A Highland Township man convicted of murdering his mother was sentenced Tuesday.

Jeffrey Pyne has been sentenced to 20 to 60 years in prison on a second-degree murder charge. His 476 days already spent in jail will go toward the prison time.

Uncut: Jeffrey Pyne found guilty of 2nd degree murder.

His mother, Ruth Pyne, was found beaten and stabbed to death May 27, 2011, in the garage of the family's home in Highland Township.

Pyne was initially charged with first-degree murder, but the judge agreed to allow for a lesser charge of second-degree to be considered if the jury could not agree on the first-degree conviction.

Pyne, 21, was valedictorian of Christian High School and was a biology student at the University of Michigan.

Pyne has maintained his innocence.

Mother was bi-polar, a schizophrenic

--Ruth Pyne

Nine months before Ruth was killed, she was jailed for attempting to strangle Jeffery. She had been committed to a mental hospital.

The prosecution argued that Jeffrey Pyne was upset with his mother and killed her in a fit of rage.

But the defense argued that there was no evidence linking Jeffrey to the crime.