By: THE CANADIAN PRESS

MEDICINE HAT, Alta. - A 32-year-old man who killed a teenage girl and dumped her body in a remote southern Alberta ditch must serve at least 18 years in prison before he can apply for parole.

That was a judge's decision Friday in sentencing Colin Winsor, who was convicted in March of second-degree murder and indecent interference. Ashton Moen, 17, disappeared in June 2006.

Her badly decomposed body was found two weeks later wrapped in a blanket and tied with cable.

During his trial, Winsor admitted to striking the teenager, but he said it was self-defence because she had come at him with a knife when he told her he didn't want a relationship with her.

On Thursday, Winsor apologized to about 15 members of Moen's family, some of whom had come from Ontario to see him sentenced.