GOLDEN — A man who brutally attacked an RTD bus driver last year was sentenced this week to 20 years in prison, according to a release from the First Judicial District Attorney's Office.

Last month, Richard Allen Mathis, 40, pled guilty to first and second degree assault.

During his sentencing hearing on Thursday, District Court Judge Diego Hunt called the assault a “savage” attack.

In February 2017, prosecutors said Mathis attacked Kolio Mintchev at Southwest Plaza.

Mintchev had reached the end of his route and asked Mathis to leave the bus. Mathis got off, but as Mintchev was checking the bus, Mathis boarded it and attacked him.

He punched Mintchev in the face and then repeatedly stabbed him with a box cutter, the news release said. While Mintchev was struggling to wrestle away the box cutter Mathis bit off a significant portion of his ear.

Despite his injuries, Mintchev managed to get the box cutter from Mathis and get off the bus. He locked Mathis in the bus until police arrived, according to the district attorney's office. When deputies attempted to take Mathis into custody he was aggressive and combative, kicking at the deputies.

Mathis said that he was heavily under the influence of methamphetamine at the time of the offense.