Phoenix police say a licensed practical nurse has been arrested on a charge of sexual assault in the impregnation of an incapacitated woman who gave birth in December at a long-term health care facility.

Phoenix Police Chief Jeri Williams said on Wednesday that investigators arrested 36-year-old Nathan Sutherland on one count of sexual assault and one count of vulnerable adult abuse.

Williams says Sutherland worked at the Hacienda HealthCare facility where the woman lived and had been providing care to her.

The 29-year-old victim has been incapacitated since the age of 3 and gave birth to a boy at the facility on December 29.

Employees said they had no idea she was pregnant. Court records say her last known physical was in April.