(CNN) A 36-year-old nurse has been arrested on suspicion of impregnating a woman in a vegetative state who unexpectedly gave birth last month at a Phoenix health care facility, police said Wednesday.

Nathan Sutherland, a licensed practical nurse who was caring for the woman at the Hacienda HealthCare facility, has been charged with one count of sexual assault and one count of vulnerable adult abuse, according to court documents from Maricopa County Superior Court.

A court order compelled Sutherland to provide a DNA sample to investigators on Tuesday, and crime lab technicians determined his DNA "matched the baby," Phoenix police Sgt. Tommy Thompson said. Sutherland was arrested on Tuesday.

A judge set a cash bond at $500,000 and scheduled Sutherland's next court appearance for January 30. The nurse is being held in the Maricopa County Jail.

Sutherland has "invoked his Fifth Amendment rights" and has not participated in an interview with police, Thompson said.

The arrest is the latest chapter in a weekslong investigation that started when the 29-year-old woman -- who is not able to give consent and has been at the facility since 2002 -- gave birth in late December.

Investigators are trying to determine whether he assaulted anyone else, or whether this woman was assaulted more than once, Thompson said.

"We owed this arrest to the victim. We owed this arrest to the newest member of our community -- that innocent baby," Phoenix police Chief Jeri Williams said at a news conference Wednesday.

The woman's family is aware of Sutherland's arrest but declines to comment further, said their attorney, John Micheaels.

Hacienda HealthCare said every member of the company is "troubled beyond words to think that a ... nurse could be capable of seriously harming a patient."

The arrest came two days after the facility announced, without elaboration, that one doctor who led the woman's care resigned, and another was suspended . The company did not name the doctors, and police did not mention them at their news conference.

'We had no idea she was pregnant'

Caretakers of the woman were surprised by the December 29 birth, with one telling a 911 dispatcher, "We had no idea she was pregnant." The woman is a member of the San Carlos Apache Tribe and has long been in a vegetative state, the tribe's chairman has said.

"The baby, I am told, is doing quite well," Thompson said, without elaborating on who is taking care of the infant.

Police began investigating the case as a sexual assault because the woman cannot give consent. Hacienda was ordered to hire a third-party manager to oversee several of its facilities.

Investigators obtained search warrants for records that helped them identify people who had access to the woman, as well as court orders to get DNA evidence from men who worked at the facility, police said.

Detectives learned that Sutherland was among those responsible for caring for the woman "during the time this sexual assault occurred," leading to the court order compelling him to provide a DNA sample, Thompson said.

At Sutherland's initial court appearance, Cohen explained the prosecution's decision to seek the significant cash bond.

"The charges in this case are very serious, the defendant sexually assaulted a very vulnerable adult who had no capacity to resist, no capacity to cry out, no capacity to do anything other than to be subject to what the defendant did to her," Cohen said.

Sutherland attorney David Gregan asked for a much lower bond, saying there was "no direct evidence that Mr. Sutherland has committed these acts," and that he anticipated that Sutherland's defense would include his own DNA expert.

Sutherland, wearing a dark shirt and jacket, said nothing other than his name and date of birth.

If he posts bond, Sutherland must be under house arrest and wear an electronic monitoring bracelet while awaiting trial, a judge said.

Sutherland has also been ordered to stay away from the Hacienda HealthCare facility and cannot contact the victim or any witnesses involved in the case, according to the court documents.

Chairman Terry Rambler of the San Carlos Apache Tribe said the tribe "hopes that justice will be served to the maximum extent allowed under the law."

Nicole Capone, a spokeswoman for Arizona Department of Health Services, said the agency's requirement for additional safety measures remains in place, including increased staff presence during interactions with patients and more monitoring of patient care areas.

Hacienda HealthCare offers apology

"Once again, we offer an apology and send our deepest sympathies to the client and her family, to the community and to our agency partners at every level," the company said in a statement Wednesday.

Sutherland had worked at the facility since 2012, Hacienda HealthCare said Wednesday. Thompson had previously said Sutherland had worked at the facility since 2011.

Sutherland, who had a current nursing license and had undergone an extensive background check before he was hired, was fired immediately Wednesday morning after the company learned of his arrest. His last shift was on Sunday, the company said.

"We will do everything in our power to ensure justice in this case," the statement said, adding that Hacienda had been cooperating with investigators.

"In the past two weeks, the Hacienda team has increased security measures to ensure the safety of all our patients. We will continue to do so. We also will continue to review and improve what is already an in-depth vetting process for caregivers at Hacienda. We will not tolerate any mistreatment of a Hacienda patient, nor will we stop until every Hacienda patient is as safe as we can make them."

Family says woman is not in a coma

CNN is not reporting the woman's name because police are investigating the case as a sexual assault.

The woman's parents said in a statement Tuesday that she has "significant intellectual disabilities" but is able to move and respond to sound.

"The victim's parents would like to make clear that their daughter is not in a coma," said the statement released to CNN by the attorney for the parents. "She has significant intellectual disabilities as a result of seizures very early in her childhood."

The woman does not speak but has some ability to move her limbs, head and neck. She also "responds to sound and is able to make facial gestures."

"She has feelings, likes to be read to, enjoys soft music and is capable of responding to people she is familiar with, especially family," the parents said.

"The important thing is that she is a beloved daughter, albeit with significant intellectual disabilities."

Woman has breathing and feeding tubes

A doctor who gave a yearly checkup to the patient about 37 weeks before she gave birth wrote that there were no major changes in her health, according to medical records sent to an Arizona court.

Medical records say the woman had an external exam April 16. A doctor noted her "firm belly" in the abdomen section. There were no notes on the forms about a pelvic exam, or urine or blood tests.

The doctor had given the woman her physicals since 2009 when a court appointed her mother as legal guardian.

The woman has breathing and feeding tubes, the records show. In March, she weighed 112 pounds.