A Lawrence County jury last month found 40-year-old Cesar Olaso not guilty of rape.
Olaso was a sergeant in the ROTC program at Black Hills State University.
Following the two-day trial, the jury acquitted Olaso on the rape charge but convicted him of providing alcohol to a minor, according to Lawrence County State's Attorney John Fitzgerald.
Olaso was sentenced to three days in jail, Fitzgerald said.
The incident involved a 20-year-old trainee in the ROTC program at BHSU.
A Sergeant in the Spearfish ROTC program charged with rape, will stand trial at the end of October.
Cesar Olaso entered a not guilty in July to forcible rape and providing alcohol to a trainee who was younger than 21 years old.
The crimes allegedly happened in Spearfish earlier this year.
If convicted, Olaso could face up to 25 years in prison for the rape charge.
The two day trial is set for Oct. 30-31.