Cheryl Lynn Suber, 30, of Garner was at Duke for treatment for Sickle Cell Anemia, but went into cardiac arrest just hours after being seen walking around the hospital in apparent good health.
She was supposed to come home on October 6, but died the day before.
The warrants say a nurse told investigators that Suber's boyfriend came out of her room and requested she check on her. The nurse went in and found no pulse.
During their response to the Code Blue, the warrants state Duke staff members found a syringe in Suber's bed that was inconsistent with her medication. The syringe was labeled saline, but was colored and opaque.
The attending physician - Doctor Daniel Kaplan - was suspicious and requested a police investigation.
The warrants state detectives seized surveillance video of anyone entering or exiting her room, they also asked to look at her medical records.
No charges have been filed in the case and police have not said if autopsy results are back that show anything was done to Suber to cause her death.
Suber's family told ABC11 Wednesday that they had not been told that her death was being treated as a possible homicide.
They say they're hurting over her death and they too would like answers. The family says they have been in contact with Suber's boyfriend and say they don't believe he had anything to do with her death.
Suber's uncle Kevin Suber read a statement issued by the family Wednesday afternoon.
"We're deeply saddened by the loss of our Cheryl," he read. "She was a loving daughter, sister, neice, cousin and friend to many. She's no longer with us and we do not know why. If there's been omission of information from the hospital or law enforcement, we would be grateful to be included in any and all communications."
Duke University Police Chief John Dailey also released a statement Wednesday about the investigation.
"The Duke University Police Department is investigating a death that occurred on Oct. 5, 2010, in Duke Hospital," Dailey said. "At the current time, we do not know the cause of death or whether a crime has occurred, although we can say that this appears to have been an isolated case and that no medical personnel were involved except in responding appropriately to the situation. Because this is an ongoing investigation and confidential patient information is involved, we are not at liberty to release other details."
Suber's obituary says she leaves behind her parents, a brother, and two sisters. Funeral services were held Tuesday.