When asked about the warrant, a police spokesman said only that the investigation was ongoing.
San Carlos Apache Police Chief Alejandro Benally says Phoenix police "will do all they can to find the perpetrator".
A Phoenix police spokesman said that "the matter is now under investigation" but declined to give any further details of the case.
The company Hacienda HealthCare told the New York Times that the resignation of executive Bill Timmons was approved by the entire board of directors.
She said no one reported that incident exclusively out of fear, and she believes there's been other abuse throughout the years.
Orman added that the facility will be cooperating with police and investigators in every way possible. No one knew she was pregnant and healthcare staff were initially unsure why she was moaning, the reports said.
The office of Arizona's governor has described the situation as "deeply troubling".
In addition to working with police, state officials are "re-evaluating the state's contract and regulatory authority as it relates to this facility and have been working closely with state agencies to ensure all necessary safety measures are in place", Patrick Ptak, a spokesperson for Ducey, R, said in a statement.
Hacienda describes itself as Arizona's "leading provider of specialised health care services for medically fragile and chronically ill infants, children, teens, and young adults as well as those with intellectual and developmental disabilities".
Phoenix police say the matter is under investigation and decline further comment.
Martin Solomon, a personal injury attorney in Phoenix whose clients are mostly vulnerable adult victims of abuse and neglect, said a lawyer representing this woman should call for all pertinent medical records, a list of current and ex-employees and any past litigation involving Hacienda. In 2013, a male employee was found to have made sexually explicit remarks to patients, though no physical or sexual abuse allegations were made and the employee was sacked.
Meanwhile, a state lawmaker is considering legislation to protect patients living at long-term healthcare facilities from abuse.