PHOENIX — A nurse who was supposed to be looking after an incapacitated woman at a long-term health care facility has been charged with raping her, weeks after she stunned her caregivers and family by giving birth to a baby boy, Phoenix police said Wednesday.

Investigators arrested Nathan Sutherland, a licensed practical nurse, on suspicion of one count of sexual assault and one count of vulnerable adult abuse, Phoenix Police Chief Jeri Williams said.

"We owed this arrest to the victim. We owed this arrest to the newest member of our community — that innocent baby," Williams said.

Sutherland, 36, submitted his DNA sample under court order Tuesday and the results came back a few hours later, showing he was a match to the baby. He declined to speak with police and invoked his Fifth Amendment rights, police spokesperson Tommy Thompson said.

Sutherland, wearing a T-shirt, black athletic pants and jacket, appeared in court Wednesday. A Maricopa County Superior Court commissioner ordered him released on a cash-only $500,000 bond. He also must wear an electronic monitoring device.

Defence attorney David Gregan had asked for a lower bond, citing the lack of a prior criminal record. He described Sutherland as a family man with young children who has lived in Arizona since 1993.

"There's no direct evidence that Mr. Sutherland has committed these acts," Gregan said. "I know at this point there's DNA. But he will have a right to his own DNA expert."

Gregan did not immediately return a message seeking comment.

Hacienda officials fired Sutherland after learning of his arrest. The company said it was "troubled beyond words." Sutherland had passed an extensive background check.

"Once again, we offer an apology and send our deepest sympathies to the client and her family, to the community and to our agency partners at every level," Hacienda said in a statement.

The 29-year-old victim has been in long-term care since age three and gave birth at the facility on Dec. 29. Employees said they had no idea she was pregnant. As her guardian, the woman's mother was required to submit an annual report to the court that included results of a medical exam.

The case has prompted the departure or discipline of key figures at Hacienda HealthCare, including the CEO. The provider says one doctor who had cared for the woman resigned and another had been suspended.

Earlier stories had described the patient as being comatose or in a vegetative state. But her parents released a statement Tuesday disputing that characterization.

They described her as intellectually disabled because of seizures in early childhood. While she doesn't speak, she has some mobility in her limbs, head and neck. She also responds to sound and can make facial gestures.

The family's attorney, John Micheaels, said in a statement that they knew about the arrest but did not want to comment.

Thompson said he believes the baby has since been released from the hospital. The woman's family has said they will care for him.