The autopsy report on Valerie Hamilton, the daughter of Concord, N.C., Police Chief Merl Hamilton, revealed on Friday that the 23-year-old died of a drug overdose brought on by a combination of cocaine and heroin.
Michael Neal, the last person to be seen with Hamilton, was arrested on a charge of murder the day after the young woman's body was found in September.
Though there were no signs of trauma to Hamilton's body, which was found on Sept. 19 stuffed in an East Charlotte locker, a lethal amount of cocaine and heroin were found in her system, while a fresh needle mark was found on her arm, according to the autopsy report.
"The question is whether [Harvey] was just present when the drugs were being consumed or whether he injected the drugs. Did he cause her to consume the toxic amount of drugs? And that's what's going to be what the DA makes the decision on," John Snyder, the former district attorney in Union County, N.C., told ABC News affiliate WSOC-TV in Charlotte, N.C. today.
"That would be a very difficult case to prove for murder," Snyder added.
Snyder said it will be difficult to find proof that Harvey, 34, forced the drugs on Hamilton, and that he expects to see a plea deal in the case. In the meantime, Snyder told WSOC, it makes sense not to drop the murder charge, so the prosecution can re-interview witnesses.
Investigators have said they believe that Hamilton, a swim teacher and triathlete, willingly left a downtown Charlotte bar with Harvey on Sept 15. The autopsy report says drug use was thought to have occurred after Hamilton left the bar.
Witnesses at the bar told investigators that at some point in the night Hamilton "appeared to need immediate medical attention" and urged Harvey to call a doctor.
"The suspect did not seek professional medical attention for Ms. Hamilton after being prompted by several independent witnesses to do so," the police statement said.
A registered sex offender, Harvey has been arrested multiple times on charges that included breaking and entering, heroin possession and possession of a firearm by a convicted felon, authorities have said.
Since his arrest in Hamilton's death on Sept. 20, Harvey has maintained that he did not murder her, and that she died of a drug overdose.
"This is not murder. There is no murder at all," Harvey, clad in an orange jumpsuit and his hands cuffed, yelled at the press. "She OD'd in her sleep. She overdosed in her sleep."
Merl Hamilton released a statement after the autopsy report was released saying that he and his family will have no public comment, as the proceedings are part of the judicial process and comments should come from "those investigating or prosecuting the case as they deem appropriate."
Merl Hamilton told ABC News' "Nightline" in an exclusive interview in September that he didn't want to know what exactly happened to her, but believes that his daughter would be alive if she hadn't met Harvey.
"I think if he wasn't with my daughter that night she would be alive," the police chief said. "She somehow was with this person, and somehow bad things happened."
Asked whether he believed Harvey killed his daughter, Hamilton replied, "I think that he contributed to her death."
Mecklenburg County prosecutor Beth Greene said the fact that Hamilton was the daughter of Concord's police chief has not and will not lead to any special treatment for the case.
"This case is being treated like any other murder case," Greene said.
Harvey's arraignment is scheduled for mid-February. He has not entered a plea on the murder charge.