A soldier stationed at Fort Wainwright was convicted and sentenced Friday for forcibly raping a girl while on base.

Spc. Nicholas Marcum, 28, was convicted of a single count of rape and sentenced to 20 years in prison by U.S. Army officers in a general court martial. As part of his sentence, he was also demoted to the rank of E-1 and is required to forfeit all pay and allowances, according to U.S. Army Alaska spokesman John Pennell.

Charges were brought against Marcum in March after the victim came forward to report not only the rape, but that Marcum had also given her alcohol. The charge of providing alcohol to a minor was dropped prior to the trial, Pennell says. The victim was 15 years old at the time of the attack.

Marcum will serve his sentence at the U.S. Disciplinary Barracks at Fort Leavenworth in Kansas. Pennell says he will be dishonorably discharged from the Army after his release.