Male employees at the US nursing home where a woman in a vegetative state gave birth will have their DNA collected by police.

Arizona authorities are desperately trying to find the man who sexually assaulted her at Hacienda HealthCare centre, which has had sexual harassment complaints made against it previously.

The 29-year-old woman - who has not been named - gave birth to a baby boy who is understood to be healthy on December 29, but a local slammed the lack of prenatal care.

The “deeply disturbing” case has prompted the CEO of the health facility to resign, with a local lawyer saying with would be difficult for Hacienda to escape liability in court.

Commenting for the first time on the investigation since the birth came to light, Phoenix police said finding a suspect is a top priority.

“She was not in a position to give consent to any of this,” police spokesman Tommy Thompson said.

“So if anyone can understand that, this was a helpless victim who was sexually assaulted.”

He didn’t release the conditions of the woman and child.

Hacienda HealthCare owns the care facility and said it welcomed the DNA testing.

“We will continue to cooperate with Phoenix police and all other investigative agencies to uncover the facts in this deeply disturbing, but unprecedented situation,” the company said in a statement.

The woman fell into the coma more than 10 years ago after a near-drowning. San Carlos Apache officials - a Native American tribe - announced she was a member of their group.

The tribe has a reservation about 215km east of Phoenix, the capital of Arizona.

A lawyer for the woman’s family said they were outraged at the “neglect of their daughter.” It’s unclear if staff members at the facility were aware of her pregnancy until the birth.

“The family would like me to convey that the baby boy has been born into a loving family and will be well cared for,” Phoenix lawyer John Micheaels said in a statement.

Officials with the San Carlos Apache tribe of southeastern Arizona said they were “deeply shocked and horrified at the treatment of one of our members”.

“When you have a loved one committed to palliative care, when they are most vulnerable and dependent upon others, you trust their caretakers,” tribal chairman Terry Rambler said.

“Sadly, one of her caretakers was not to be trusted and took advantage of her. It is my hope that justice will be served.”

San Carlos Apache police chief Alejandro Benally said Phoenix police “will do all they can to find the perpetrator.”

A spokesman for Hacienda HealthCare, David Leibowitz, said investigators served a search warrant Tuesday to obtain DNA samples from all male staffers - a day after company CEO Bill Timmons stepped down.

Board member Gary Orman said the facility “will accept nothing less than a full accounting of this absolutely horrifying situation.”

“We will do everything in our power to ensure the safety of every single one of our patients and our employees,” Orman said in a statement.

The Hacienda facility serves infants, children and young adults who are “medically fragile” or have developmental disabilities, according to its website.

After the reports, the Arizona Department of Health Services said new safety measures have been implemented, including increased staff presence during any patient interaction, more monitoring of patient care areas and additional security measures involving visitors.

The state’s online complaint database for care facilities shows multiple complaints about the Hacienda centre going back to 2013. Most of them involve fire drill and evacuation preparation or Medicaid eligibility. But one complaint from December 2013 outlines an allegation that a staff member made inappropriate sexual comments about four patients two months earlier.

Martin Solomon, a personal injury lawyer in Phoenix whose clients are mostly vulnerable adult victims of abuse, said it would be difficult for Hacienda HealthCare to escape responsibility in court.

“There’s a lot of information we do not have. But things like this don’t happen without someone either knowing about it or should have known about it,” Solomon said.