A Phoenix police spokesman said that “the matter is currently under investigation” but declined to give any further details of the case.
Protocol at the clinic has been changed, the source said, and men now have to be accompanied by a woman on entering the room of a female patient.
Hacienda HealthCare said it was fully co-operating with the authorities.
The Arizona Department of Health Services said it had sent inspectors to check on patients at the facility and had implemented “heightened safety measures”.
On its website, Hacienda HealthCare says it provides care for “medically fragile and chronically ill infants, children, teens, and young adults as well as those with intellectual and developmental disabilities”.