Howard Gregg Diamond ran a booming pain management practice with clinics in Sherman, Sulphur Springs and Paris.

Patients came from all over North and East Texas, as well as Oklahoma, to see Diamond, who fancied himself a musician in his private time. Business was so brisk that in 2014, he ranked No. 2 among all specialties of doctors for prescriptions for both morphine and oxycodone, according to ProPublica’s analysis of Medicare data.

Now, the popular doctor finds himself in big trouble, accused in the overdose deaths of seven patients between 2012 and 2016. Three of the deaths happened in Texas in the cities of Sulphur Springs, Abilene, McKinney. The rest were in Oklahoma.

Investigators are also looking into numerous other deaths of his patients.

The indictment accuses the 56-year-old doctor of drug distribution, defrauding Medicare and money laundering. He was taken into custody Tuesday.

His attorney, Pete Schulte, says Diamond is cooperating with federal investigators. “Dr. Diamond hasn’t done anything wrong,” Schulte said. “He makes sure that people that are prescribed medications know how to take it, but you can’t stop people who want to overuse prescription medicine and take their own lives. That’s what we’re prepared to show.”

The investigation into Diamond began after WFAA’s investigative news reports about McKinney doctor Randall Wade. He is accused of prescribing massive amounts of painkillers to his patients.

Wade was indicted last fall in connection with the death of one patient. He has been linked to seven others, according to court testimony.

Wade tended to prescribe the traditional opioid-based drugs, such as hydrocodone. What makes Diamond different is that he was prescribing those, too, but added in powerful, even more lethal narcotics like morphine, methadone and fentanyl, according to court records.

Brewing Trouble

Trouble began brewing for Diamond several months ago. Just like Wade, pharmacies had begun refusing to fill Diamond’s prescriptions.

On April 16, he posted on his clinic’s Facebook page that “most of the pharmacies in my region…have stopped filling prescriptions for my patients.”

He described it as an “unexplained circumstance that is out of my control and inconsistent with the medical welfare of my patients.”

Diamond asked his patients to send emails to an email account describing the situation had negatively impacted their lives. He further asked that they provide details about what the pharmacies had told them about why they were unable to fill his prescriptions.

In May, the Drug Enforcement Administration and FBI agents raided his Diamondback Pain and Wellness centers in Sherman and Paris. At the time, the FBI said it was for failing to maintain sufficient medical records.

On June 23, he posted that he was doing the best he could to keep his practice open and to manage the demands that the “government” might have for him. The post said that he was closing down the Sulphur Springs office due to lack of manpower.

A grand jury issued a sealed 21-count indictment on July 6. He was taken into custody Tuesday.

Many patients have taken to Facebook to voice their support for Diamond.

“The government ruined a good doctor’s life,” one wrote. Another wrote, “He is a good man and a great Dr.”

“Looked like a methadone clinic”

Vincent Calabrese' mom began going to Diamond's Sherman office last year after being referred there by her primary doctor. She is disabled, so he would take her to the appointments.

Those appointments were an all-day affair. A nurse told him Diamond saw 75 to 100 patients a day. “It looked like a methadone clinic,” Calabrese said.

He says his mother was prescribed massive amounts of painkillers and only saw Diamond one time. “If she took half of what he prescribed, she was a zombie,” he says.

Calabrese says his mother told the nurse that she didn’t need that many pills, but Diamond refused to reduce the prescription amounts.

“The nurse said if he cuts you back, it’s going to look like he over prescribed you,” he said.

Calabrese says one time a woman failed a drug test and then asked another woman if she took any pills.

“One of the nurses walked by and heard it and said, ‘Oh I’ve seen that several times,’’ he says.

Another time, a young woman approached him offering him half her pills if he paid for her prescription.

“I mentioned it to the girl up front and he said, ‘Oh it happens,’” he said.

He quit taking his mom to Diamond last month after he couldn’t find a local pharmacy to fill his mother's prescriptions and had to drive all the way to Waco.

Her new doctor was shocked at the amounts Diamond had been given her. “He said, ‘Why would he ever give you this? You’re almost 60 years old. You have high blood pressure. You have anxiety, you have blood clots,’” Calabrese said.

Calabrese also knew one of the seven people who died. He says his friend went into a coma and died in 2015.

A former Diamond patient, who requested not to be named for privacy reasons, began going to Diamond about five years ago after a car wreck. He says the doctor began prescribing him large amounts of pain killers.

“The amount of oxycontin he had me on was enough to knock a horse out,” the former patient said.

One day, he says he was shocked when a prescription for liquid fentanyl, a high-powered opioid from a New York pharmacy, showed up in the mail in 2014. He says he and Diamond had never discussed it beforehand.

“I’m smart enough to know that with the medications he was already giving me that there was no way I could take that, too,” the former patient said.

He says he threw it away and told Diamond not to prescribe it to him again.

“He had me in bad, bad shape,” he said. “He was supposed to be managing my pain, but really, I was to the point where I thought I could die at any minute.”

WFAA interviewed other patients who had nothing but good things to say about Diamond.

Shelley Diane Hervey, who live just near Paris, went to Diamond for 10 years. “He was an outstanding doctor,” she said.

Hervey says he treated her carpal tunnel syndrome with injections so that she did not have to have surgery. “I never saw anything out of the way that he did,” she said.

In fact, Hervey said she knows of people that he stopped seeing because they had been abusing the medications.

Kimberly Martinez, a Bonham resident, calls him a wonderful doctor who helped people who needed help. “I don’t think it’s very fair that he’s being accused,” Martinez said. “Not everybody abuses their medicines. He never overprescribed me.”

Driving passion

In a March YouTube video, Gregg Diamond says his goal was to improve is patient’s lives and reduce their pain.

“Medication abuse and issues is a huge concern in our society and our government has become very, very strict,” he says looking into the camera while seated at his desk.

He made another video while attending a Tony Robbins conference in Las Vegas in August 2016.

“One of my driving passions is to offer more to my patients and be the best,” he said in the video.

WFAA was there Thursday morning outside Diamond's office in Sherman. His name was still on the door. By the afternoon, his name had been scraped away.

Diamond faces up to life in prison, forfeiture of his property and millions in fines.

He is currently being held in the Fannin County jail. A judge will decide on Friday if he should remain in federal custody pending trial.

“He was a pill pusher like plain and simple,” Calabrese said. “Honestly, I think what got him was greed.”