The outlet also reported that the patient has been in a vegetative state for at least a decade after almost drowning.
The woman had been a patient at the Phoenix facility for years after nearly drowning, according to azfamily.com, which broke the story; police declined to provide NPR with details about their investigation.
The Arizona Department of Health Services told the Arizona Republic that in the wake of the news that a woman gave birth, the facility is required to have heightened security measures including increased staff presence during patient interactions, increased monitoring of patient care areas, and increased security measures with respect to visitors to the facility.
"None of the staff were aware that she was pregnant until she was pretty much giving birth", a source familiar with the situation said.
"To that end, we are re-evaluating the state's contract and regulatory authority as it relates to this facility and have been working closely with state agencies to ensure all necessary safety measures are in place".
Gov. Doug Ducey's office has called the situation "deeply troubling".
San Carlos Apache Police Chief Alejandro Benally said Phoenix police "will do all they can to find the perpetrator" and his department will assist "in any way possible".
"In a statement, board member Gary Orman said: "[We] will accept nothing less than a full accounting of this absolutely horrifying situation".
State records show complaints about Hacienda de Los Angeles going back to 2013.
The reported birth - and the sexual assault on a vulnerable individual that must have preceded it - has cast a harsh glare on conditions at a nonprofit organization that bills itself as a leading provider of health care for Phoenix's medically fragile. The employee was sacked.
In the statement, the lawyer, identified as John Michaels, said the family is "outraged, traumatized, and in shock by the abuse and neglect of their daughter at Hacienda Healthcare".
Richardson says even if police need to keep parts of the investigation confidential, they should tell the public that. "But things like this don't happen without someone either knowing about it or should have known about it", Solomon said.
All they've said is they're investigating "a matter".
"What do we know about the baby?" asked Whitney.
Jon Meyers, executive director of The Arc of Arizona, an advocacy group for people with intellectual and developmental disabilities, called the allegations "disturbing, to put it mildly".
"From what I know the baby is alive, and the baby is healthy", she said.
"From what I've been told, she was moaning", an unidentified source told Phoenix CBS affiliate KPHO.