A Chester County massage therapist is accused of sexually assaulting a female client during an appointment.

The Chester County District Attorney's Office said 63-year-old James Deiter inappropriately touched the victim during her appointment at Massage Envy, at 1107 West Chester Pike in West Goshen, on Saturday.

The victim called police after the incident.

Prosecutors said the 55-year-old woman was naked and alone with Deiter when the alleged assault happened.

The victim told police that "at no time did she do or say anything" that "could be construed as asking Deiter to touch her in a sexual manner" during the appointment, a criminal complaint says.

The woman told investigators she had received massages from Deiter once a month since September.

Deiter "groomed the victim by providing massage therapy a number of times before sexually assaulting her," First Assistant District Attorney Michael Noone said in a statement. "He waited until he had earned her trust over a number of appointments before assaulting her."

Prosecutors said Deiter, of Holtwood, had worked at Massage Envy for a year and was fired after the allegations surfaced.

Deiter is facing charges of aggravated indecent assault and indecent assault. He is being held at the Chester County prison on $25,000 bail.