COLORADO SPRINGS, Colo. » A former Army officer who once blamed his twin brother for a string of sexual assaults on young girls has been sentenced to 20 years to life in prison.

The Colorado Springs Gazette reports Aaron Lucas was sentenced Friday.

Lucas had been assigned to Fort Carson outside Colorado Springs. He said last year his twin was responsible the attacks but in November he changed his mind and pleaded guilty.

Authorities say the twin denied involvement.

Investigators say DNA linked Aaron Lucas to the abduction of an 8-year-old girl in Colorado Springs and to cases in Alabama and Texas.

Prosecutors dropped some of the Colorado charges and Lucas agreed to not fight extradition to Texas for a 2009 case. Alabama authorities agreed not to pursue charges for another case.