She had been left in a vegetative state (awake but with no signs of awareness) for over 10 years after nearly drowning.
Police served the long-term care facility with a search warrant on Tuesday, The Associated Press reported.
An attorney for the family of the vegetative woman said on Tuesday that the baby boy is healthy but it's not clear who now has custody of the child, reported KPHO.
In a statement, board member Gary Orman said Hacienda "will accept nothing less than a full accounting of this absolutely horrifying situation".
Thompson said the sexual assault investigation will take some time.
The caregiver said the woman was completely unable to communicate and was only visited by family members every few months.
In a statement released to PEOPLE on Friday, Hacienda HealthCare spokesman David Leibowitz said the organisation, which runs the facility, was cooperating with authorities, but declined to divulge the exact nature of the underlying incident.
It would be the police who would lead DNA testing to figure out who fathered the baby, Solomon said, adding that it would be hard for Hacienda to escape liability.
"And we will do everything in our power to ensure the safety of every single one of our patients and our employees". "Timmons' resignation was accepted unanimously by the Hacienda Board of Directors".
The birth has prompted a sexual abuse investigation at the nursing facility, The Mirror reports.
Gov. Doug Ducey's office has called the situation "deeply troubling".
In 2013, Timmons received a warning from the Arizona Department of Health Services after an investigation revealed that a staff member - who was later fired - had made sexual comments about a patient that weren't appropriately reported.
The family obviously is outraged, traumatized and in shock by the abuse and neglect of their daughter at Hacienda Healthcare.
One staff member was sacked for making repeated inappropriate sexual comments to patients.
"We don't know who this person is yet".
State officials say they have acted to protect other patients following the pregnancy.
"From what I've been told she was moaning and they didn't know what was wrong with her".
According to federal records, the healthcare facility where the woman gave birth has at least 74 patient beds.