(NEWS CENTER) -- The Maine Supreme Court has upheld the conviction of a former music teacher from Pittsfield who was found guilty of repeatedly abusing his ex-girlfriend over a period of several months.

The high court's opinion, released Tuesday, rejected 30-year-old Andrew Maderios' argument that the trial court made an error in allowing testimony from certain witnesses and evidence to be admitted.

The former Nokomis Regional High School teacher was convicted of aggravated assault and domestic violence assault charges last year.

Prosecutors say Maderios beat, kicked and strangled his then-girlfriend on multiple occasions.

The victim told the court at Maderios' sentencing that her fear of dying was "overwhelming" and she was sorry that she "brought a monster" into the lives of her children.

Maderios received a 15-year prison sentence for the crime.