According to charging documents, a woman reported seeing Rebstock brush by an 11-year-old girl and grab the girl's buttocks at the Festival of Trees in November 2012. The woman talked to the girl and confirmed what had happened, then reported it to security at the South Towne Exposition Center.
Rebstock tried to run when security guards approached, police said, but was eventually caught by the alleged victim's father and security officers, who arrested him.
Rebsotck was still on parole for the 2001 offense at the time.
Rebstock, who was added to the Utah sex offender registry after his release on parole in March 2009, has been in and out of prisons since he was 16 years old.
As a teen, Rebstock pleaded guilty to manslaughter in the 1982 death of Lara Deutsch, a 12-year-old New Orleans girl who lived near Rebstock and was friends with his little sister.
Rebstock was eventually released in half the time he was sentenced to serve due to a legal technicality.
While in prison in Utah for the 2001 sexual abuse conviction, Rebstock received a year of sex offender therapy, according to audio recordings of his parole hearings.
His most recent sentence, handed down Monday by 3rd District Judge Terry Christiansen, will run concurrent to any other sentences he is already serving.