The police in the United States have opened a sexual assault investigation after a woman said to have been in vegetative state for at least a decade at a private medical facility in Phoenix, Arizona, reportedly gave birth on December 29, CBC News reported.

None of the staff at the Hacienda Healthcare facility allegedly knew that the woman was pregnant. “So when she went into labor a few days after Christmas, her caretakers were flummoxed,” an unidentified source told the KPHO news channel, an affiliate of CBS News in Phoenix. “And they didn’t know what was wrong with her...None of the staff were aware that she was pregnant until she was pretty much giving birth.”

The woman, assisted by a nurse at the facility, gave birth to a boy. A Phoenix police spokesperson told The Washington Post that the department was investigating the case but did not release details about the case. Arizona Governor Doug Ducey’s office released a statement saying the reports are “deeply troubling.”

Hacienda HealthCare is an umbrella organisation for several programs in the Phoenix area that treat chronically ill infants, children and adults. In a statement released to ABC News, the organisation’s spokesperson David Leibowitz said that “as an organization, Hacienda HealthCare stands fully committed to getting to the truth of what, for us, represents an unprecedented matter”.

The organisation released another statement, saying it was conducting a comprehensive internal review of its processes, protocols, and people to ensure that residents at its facilities remain safe. “Anything less than that is unacceptable to our team, our company’s leaders and the communities we serve,” it added.

The Arizona Department of Health Services, which regulates healthcare facilities, said the 60-bed facility has to tighten security procedures to protect patients in wake of the report. “We are aware of this situation and are actively working with local law enforcement in their criminal investigation,” the department added.