GRAND JUNCTION, Colo. (KKCO) -- A former youth volunteer is sentenced to at least twelve years behind bars for sexually assaulting four boys.

Thursday, Mesa County Judge Richard Gurley ordered Mark Bustamante to serve two indeterminate, consecutive sentences of six years to life.

Three of his four victims sat in on the sentencing, all visibly upset. They were joined by parents and grandparents for support.

With tears in his eyes, Bustamante gave two statements to apologize for his actions. He told the victims that no words can undo what he did, and all he can give them now is closure.

The judge said he took note of Bustamante's remorse.

Bustamante had sexually assaulted the boys while he volunteered as a Mesa County Partner and a youth coach for the City of Grand Junction. He pleaded guilty to the crimes in November 2012.