Coconino County prosecutors say 22-year-old Gregory Woody Jr. is facing 14 counts including kidnapping, sexual assault, attempted sexual assault, aggravated assault, assault and sexual abuse.
Authorities say the assaults were first reported in January.
Woody was arrested Aug. 15 at his home and authorities say he remains in custody.
It was unclear Friday whether he had a lawyer yet.
Flagstaff police say they began watching Woody last month after he reportedly had an encounter with a female undercover officer.
Woody voluntarily provided a DNA sample, which authorities say matched to samples collected from victims of the alleged assaults.