Azad Khan signed progress notes for hundreds of patients at the South Philadelphia drug-treatment clinic, indicating he had performed a physical exam on each and had provided drug-treatment counseling.

Yet in case after case, the written results from the exams were identical, with only the patient's name and date changed.

The reality, according to federal prosecutors: Khan generally was not examining or counseling the patients, but was part of an illegal "assembly-line" scheme to sell opioids.

After a seven-day trial that ended Tuesday, a jury agreed, convicting the 63-year-old Villanova resident of conspiracy and two counts of distributing drugs.

Robert J. Livermore, an assistant U.S. attorney who prosecuted the case with colleague Katherine E. Driscoll, said federal guidelines call for Khan to receive a sentence of 41 to 51 months in prison.

"This was a medicine-free clinic," Livermore said Wednesday. "Basically it was in and out. They only saw Dr. Khan as long as it took for him to sign the prescription."

Khan worked part time at the now-defunct clinic at 2300 S. Broad St. for less than a year, from mid-2013 to March 2014. The operation was run by physician Alan Summers, who pleaded guilty in February to conspiracy, distribution, money laundering, and health-care fraud. Both are scheduled to be sentenced in October by U.S. District Judge Lawrence F. Stengel.

A third physician at the clinic, Keyhosrow Parsia, also has pleaded guilty in the case and awaits sentencing. He testified against Khan during the trial that finished Tuesday.

Prosecutors say that from 2001 to 2014, Summers took in $5 million in cash from patients who underwent little to no medical examination, giving them hundreds of thousands of doses of an opioid-containing drug called Suboxone. That opioid has weaker effects than heroin and other opioids, and thus is used in treatment programs, but it, too, can be abused.

In order to prescribe Suboxone, physicians are required to perform detailed medical exams, offer counsel about the risks of the drug, and analyze the results of urine samples to make sure the patients are taking it. Summers and Khan generally failed to do so, and instead doled out Suboxone based on how much cash the patient could pay, not based on what was medically advisable, Livermore said.

In many cases, patients simply were reselling the drug on the street, he said.

Khan prescribed 110,000 doses of Suboxone while at the clinic, at $200 for a month's supply. Summers paid him a percentage of each cash payment, totaling $147,000 over the course of less than a year of part-time work.

Defense attorney Jeffrey M. Miller praised Stengel as running a fair trial but said he was disappointed in the jury's decision. He said many of Khan's patients had a legitimate medical need for Suboxone.

During the trial, the jury heard testimony from an undercover Philadelphia police officer who posed as a patient on several visits to the clinic. He testified that on one occasion, Khan refilled his prescription without analyzing the results of a urine sample, which would have shown that he was not using Suboxone or any other opioid.

On another occasion, Summers said patients could earn a $50 referral fee for every new patient they brought in, the undercover officer testified.

Also part of the investigation were the U.S. Drug Enforcement Administration and the Office of Inspector General at the U.S. Department of Health and Human Services.