Last month, police announced two men had been charged with sexual assault and procuring the girl for the purposes of prostitution.
In a separate incident, police say the girl accepted a ride home last summer from a man she had met downtown, and was subsequently sexually assaulted.
An arrest in the case was made late last week.
Casey Lane Sweet Grass, 31, of Standoff, Alta., is charged with sexual assault, sexual interference and invitation to sexual touching.
He is to appear in court March 15.