An Orange County doctor has been arrested on suspicion of illegally selling powerful narcotics to a man who is suspected in a DUI crash that killed a Costa Mesa fire captain, as well as selling drugs to five people who went on to fatally overdose, local officials with the Justice Department announced Tuesday.

Dr. Dzung Ahn Pham, 57, faces federal drug trafficking charges and two counts of illegally distributing oxycodone and issuing prescriptions for controlled substances outside the usual course of professional practice and without a legitimate medical purpose.

Pham, of Tustin, would allegedly write prescriptions for so-called patients who were drug addicts and/or were selling the drugs on the black market, according to a news release from the U.S. Attorney’s Office for the Central District of California.

The doctor, who owns Irvine Village Urgent Care, would supply the drugs without a medical examination, and at least five people who obtained prescriptions from Pham suffered overdose deaths between 2014 and 2017, the release states.

“This case clearly and tragically illustrates the dangers of drug dealers armed with prescription pads,” U.S. Attorney Nick Hanna said. “This doctor is accused of flooding Southern California with huge quantities of opioids and other dangerous narcotics by writing prescriptions for drugs he knew would be diverted to the street.”

Pham was arrested by federal Drug Enforcement Administration special agents on Tuesday morning following an investigation that began in 2015.

A 71-page affidavit filed Monday by DEA Special Agent Lindsey Bellomy ties Pham to two high-profile recent crimes in Southern California.

The man charged with murder in the death of Costa Mesa Fire & Rescue Capt. Mike Kreza, who was cycling when he was fatally struck Nov. 3, told investigators he “was on medications prescribed by Pham,” the affidavit states. Driver Stephen Taylor Scarpa of Mission Viejo allegedly had several prescription bottles with Pham’s name in his vehicle when the crash occurred.

Pham is also linked to the gunman in the Nov. 7 Borderline Bar & Grill mass shooting in Thousand Oaks. In a text message, Pham “expressed concern” that shooter Ian David Long, who left 12 victims dead, was found to have in his possession medication that Pham had prescribed for someone else, the news release states.

It is unclear whom the prescription was originally for, but the person Pham texted assured the doctor he wasn’t culpable in the massacre.

“Thats not on you, if i give my meds to some crazy person its on me, not you, you have no control over what happened after a patient leaves your office,” the person texted Pham.

Pham allegedly issued “an extremely high amount” of prescriptions over a three-year period, including adderall, oxycodone, tramadol, suboxone, norco, soma, alprazolam, and hydrocodone bitartrate-acetaminophen. The drugs he prescribed would lead to “higher risks of addiction, overdose and overdose deaths,” the affidavit states.

Pham profited greatly from writing illegal prescriptions, officials allege. The doctor charged between $100 and $150 per office visit to the clinic he owned, Irvine Village Urgent Care at 15435 Jeffrey Road, Unit 127, in Irvine. The clinic is in a strip mall near several restaurant and a dental office. It bears a sign stating “Dr. Pham” out front.

Between 2013 and September 2018, Pham deposited over $5 million, mostly in cash, into bank accounts held by him and and his wife. He also deposited approximately $1.7 million, believed to have derived from insurance payments, into a business bank account.

A CVS pharmacy stopped accepting prescriptions from Pham more than five years ago after the pharmacy could not justify the number of opioid pills the doctor was prescribing to individual patients, the Justice Department release states.

During undercover operations earlier this year, a DEA agent was able to “quickly and easily” obtain prescriptions for narcotics from Pham, officials said. Those included a “triple threat” or “holy trinity,” a combination of an opioid, a benzodiazepine (like Valium) and a muscle relaxer. Pham then told the agent that CVS would not fill his prescription for hydrocodone and to visit Bristol Pharmacy in Irvine and ask for “Jennifer N.” The agent was able to fill the prescription at the pharmacy, at 250 E. Yale Loop, Unit C, after speaking to “Jennifer N.”

The undercover agent returned about a month later saying she was having issues with stress that might be triggering her lower back pain, and Pham prescribed two additional medications that the agent was able to fill.

According to the affidavit, at least 84 of Pham’s patients got their prescriptions filled the same day or within two days after sending the doctor text messages requesting specific quantities of narcotics. Many of them were around the same age – between 25 and 40 – and lived at the same address as other Pham patients.

Much of investigators’ information was obtained from a California state database of prescriptions for controlled substances called the Controlled Substance Utilization Review and Evaluation System, or CURES. In a three-year period from 2014 to 2017, Pham wrote 52,419 prescriptions to about 2,400 unique patients, or about 334 prescriptions per week, according to Bellomy’s affidavit.

“This is an extremely high amount,” the affidavit states.

Pham was scheduled to appear in federal court in Santa Ana on Tuesday. He faces a maximum sentence of 40 years in prison if convicted as charged.