PHOENIX, Arizona (NYTIMES) - Police in Phoenix have opened an investigation into allegations that a woman in a vegetative state at a private nursing facility was sexually assaulted and gave birth to a child last month, the authorities said on Friday (Jan 4).

Sergeant Tommy Thompson, a spokesman at the Phoenix Police Department, said detectives were looking into the case at the facility, which provides long-term care for people with intellectual disabilities.

Thompson declined to elaborate on how long the investigation had been open or other specifics about it.

The woman has not been publicly identified.

A spokesman at the Arizona Department of Health Services said the agency was aware of the allegations and had already sent inspectors to check on patients at the institution, which is around 10km south of downtown Phoenix.

The facility is part of Hacienda HealthCare, which its website describes as an organisation for some Phoenix-based healthcare programmes and services.

"During this time, the agency has required heightened safety measures be implemented at the facility, including increased staff presence during patient interactions; increased monitoring of the patient care areas; and increased security measures with respect to visitors at the facility," the spokesman, Melissa Blasius-Nuanez, said on Friday.

A spokesman at the Hacienda facility did not immediately respond to an e-mail on Friday seeking comment.

The institution has at least 74 patient beds, according to federal records, and cares for people who have a range of developmental conditions and cognitive abilities.

Some patients have been there for decades, according to state records.

In 2013, the Arizona Department of Health and Human Services found that a male employee at the facility had mistreated some patients by making sexually explicit remarks about them.

In one episode, his colleagues overheard him tell a patient that the patient was going to have a "happy morning" because the employee's penis was erect, the state found.

In that report, investigators did not mention any instances of suspected physical abuse.

The facility's operators told the state that the male employee had been fired and new training on reporting patient abuse had been implemented.

In 2017, state investigators cited the facility for not providing privacy to patients while they were naked and being showered.

One patient complained that he felt uncomfortable when employees freely walked into the shower room when he was naked, according to a state report.