Two years ago, just 24 hours after being released from rehab, Audrey Rae Austin returned to the man who provided her with pills.

Jonesboro psychiatrist Dr. Narendra Nagareddy had not seen the 29-year-old Forest Park woman in five months, yet law enforcement officials say he gave her a prescription for 90 tablets of a strong sedative and 90 tablets of Methadone. The woman returned to his office the very next day and got a prescription for 60 amphetamine pills. Austin overdosed that day. She was put on life-support and died two days later on Feb. 23, 2014.

Authorities say Austin is one of 36 of Nagareddy’s patients who have died while being prescribed controlled substances from him.

On Thursday, some 40 federal and local agents raided Nagareddy’s office on Arrowhead Boulevard in Jonesboro where he was arrested and led out in handcuffs. They also seized items from his McDonough home. A preliminary hearing has been set for Feb. 9 at 8 a.m.

Nagareddy was preparing to post his $100,000 bond late Friday.

“He stands on his innocence,” said Steven Frey, Nagareddy’s attorney. “We look forward to getting him out of jail and preparing his defense.”

Clayton District Attorney Tracy Graham Lawson told The Atlanta Journal-Constitution Friday that authorities suspected Nagareddy over-prescribed pain medication to 36 patients who died. According to the autopsies on 12, they all died from drug overdoses.

Nagareddy is facing one felony drug charge for illegally prescribing pain medications, but authorities say more charges are likely when he’s indicted.

“They took thousands of records [during the raid] and it most likely will take several months to go through the records,” Lawson said.

Nagareddy’s arrest comes after more than a year of undercover investigations and interviews with medical professionals as well as current and former patients. Although this was a joint local-state-federal operation, the charges will be brought in state court rather than federal court.

The investigation found that Nagareddy “often prescribes controlled substances refills for up to five months, had excessive patient wait times and scheduled appointments for every three to five months,” according to the state warrant.

Clayton Police Chief Michael Register told Action News Channel 2 that “If the allegations are true, he is Dr. Death.”

On Friday, a voicemail message at Nagareddy’s business, Psychiatry Associates of South Atlanta, told callers the office was closed permanently.

On Nov. 25, 2014, investigators submitted a search warrant for the Georgia Prescription Drug Monitoring Program database. They ran patients’ names through local databases to see if there were any additional prescription overdose deaths tied to Nagareddy. They initially found 25 of Nagareddy’s patients who had died.

Four months later, investigators went to the Walgreens pharmacy in Conyers to get information on one of Nagareddy’s patients who had died. While there, Walgreens pharmacist Cosima Niau told investigators that “she believed Nagareddy was prescribing outside his scope of practice, as Dr. Nagareddy is a psychiatrist and was writing prescriptions for pain medication.”

Niau showed investigators a prescription written by Nagareddy for Percocet which she said she refused to fill. She also told investigators she had turned down prescriptions written by Nagareddy for other pain medications in the prior six months.

Shortly after that, investigators learned of Austin’s death. Austin’s mother, Ruth Carr, told investigators her daughter had “been in a bad way for years.” She had abused methadone when she was younger. Carr also said her daughter was addicted to methamphetamines before she saw Nagareddy.

Carr said in the arrest warrant that she doesn’t blame Nagareddy for her daughter’s death, but “he made it easy for her to get it (prescription medication).”

Staff writer Rhonda Cook contributed to this article.