PHOENIX (Reuters) - An Arizona male nurse has been charged with raping a severely disabled woman at the long-term care facility where he worked, a crime that came to light only after she gave birth, prosecutors said on Wednesday.

Nathan Sutherland, 36, was arrested by investigators who linked him to the case through DNA evidence after the woman, who is in her 20s, unexpectedly gave birth on Dec. 29 at Hacienda Healthcare Skilled Nursing Facility in Phoenix.

“From the minute we first became aware of this crime, a sexual assault, we have worked virtually non-stop every day, every night, seven days a week trying to solve and resolve this case,” Police Chief Jeri Williams told a news conference.

Williams said the case, which has made international headlines, was solved through a combination of DNA and “good old fashioned police work.”

Sutherland, a licensed practical nurse who began working at Hacienda Health care in 2012, was charged with one count each of sexual assault and abuse of a vulnerable adult. He was ordered held on $500,000 bail during a brief appearance in Maricopa County Superior Court.

Reuters could not reach Sutherland’s defense lawyer for comment on Wednesday.

The Arizona Republic newspaper reported that attorney Dave Gregan said during the hearing that there was no direct evidence against his client, who had no criminal history, and that the defense planned to conduct its own DNA tests.

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The woman, who has been disabled since very early childhood as a result of seizures, has spent most of her life in Phoenix’s Hacienda Healthcare.

Though she was initially described as comatose, her parents said in a written statement that although she was disabled she could respond to sound, make facial gestures and had some ability to move her limbs, head and neck.

“The important thing is that she is a beloved daughter, albeit with significant intellectual disabilities,” they said.

The parents declined to comment on Sutherland’s arrest in a separate statement issued through their attorney.

Hacienda employees were not aware that woman was pregnant before she went into labor, police say, and were first alerted to the case when the baby was born. Police then sought DNA samples from all male employees.

The facility said in a written statement that Sutherland was fired as soon as administrators learned of his arrest.

“Before he started work with Hacienda, he underwent extensive background checks, including an extended criminal history search; a search of multiple government registries, including sex offender registries and Arizona Department of Economic Security and Child Protective Services registries; and checks of his personal references,” it said.

The baby, a boy who is being cared for by family members, is doing well, police said.