HARRISBURG, Pa. (KDKA) — The Pennsylvania Supreme Court upheld the conviction and prison sentence of 22-year old Alex Hribal on Monday.

Hribal pleaded guilty to 43 counts in 2017 following a knife attack at Franklin Regional High School in 2014.

According to the Tribune-Review, Hribal’s attorney, Patrick Thomassey, had argued that Westmoreland County Judge Christopher Feliciani made a mistake when he did not transfer Hribal’s case to juvenile court.

Thomassey also claimed that the sentence of 23-1/2 to 60 years in prison was too severe.

If Hribal had been convicted in juvenile court, Hribal could not have been held past his 21st birthday under state law.

Hribal was arrested when he was 14 years old after wounding 20 teens and a security guard during a 2014 knife attack at Franklin Regional High School in Murrysville.

Hribal pleaded guilty to 43 counts in 2017, including charges of attempted murder and aggravated assault.

He was sentenced to 23 & 1/2 to 60 years in prison by Judge Feliciani.

According to the Tribune-Review, Hribal is serving his sentence at SCI Albion in Erie County.