Georgia psychiatrist Narendra Nagareddy has been indicted on three counts of felony murder and 59 counts of unauthorized distribution of prescriptions after at least 12 of his patients died due to an overdose of pain medication.

Investigators said Nagareddy, 57, has also been linked to the deaths of 36 total patients to whom he prescribed controlled substances including oxycodone, methadone, hydrocodone, and amphetamine. He prescribed these substances for “no legitimate reason,” according to CBS News. Thirty-three of the patients were not presented in the affidavit because they did not die in Clayton County.

“There will no longer be prescriptions issued by Dr. Nagareddy that result in the deaths of any innocent people,” said Clayton County District Attorney Tracy Lawson to Fox News.

The county charged Nagareddy in the deaths of his former patients David Robinson, 49; Cheryl Pennington, 47; and Audrey Austin, 29. According to the Atlanta Journal–Constitution, he was known as the go-to physician for prescription drug addicts all over the south side of Atlanta and, since his arrest, has garnered the nickname “Dr. Death.”

The doctor has maintained his innocence. He told CBS affiliate WGCL in March: “I’m an honest man. I look after all the severely mentally ill patients, please understand, sir.”

Nagareddy’s arraignment is scheduled for July 7, and trial is set to begin Aug. 8.