All male employees at a care facility, where a female patient who had been in a vegetative state for years gave birth, will have to provide DNA to police.
Police served a search warrant on Tuesday to get DNA from the male employees at the long-term care facility in Phoenix.
Hacienda HealthCare said it welcomed the DNA testing of employees.
"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, who had been in a vegetative state for more than 10 years after nearly drowning, gave birth to a healthy baby on 29 December.
Officials from the San Carlos Apache tribe announced on Tuesday night that the woman was a member of their community and confirmed she was still in a vegetative state when she gave birth.
"On behalf of the tribe, I am deeply shocked and horrified at the treatment of one of our members," tribal chairman Terry Rambler said.
"When you have a loved one committed to palliative care, when they are most vulnerable and dependent upon others, you trust their caretakers.
"Sadly, one of her caretakers was not to be trusted and took advantage of her. It is my hope that justice will be served."
A lawyer for the woman's relatives said the family, who wish for privacy, were outraged at the "neglect of their daughter" and "would like me to convey that the baby boy has been born into a loving family and will be well cared for".
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, Hacienda HealthCare board member Gary Orman said the facility "will accept nothing less than a full accounting of this absolutely horrifying situation."
Hacienda CEO Bill Timmons stepped down Monday.
The state's online complaint database for care facilities shows complaints about Hacienda de Los Angeles going back to 2013, most of which involve fire drill and evacuation preparation or Medicaid eligibility.
One complaint from December 2013 outlines an allegation that a staff member made inappropriate sexual comments about four patients two months earlier.
The incidents were not relayed to an administrator and the employee was later fired.