CHICAGO (CBS) – The former owner of a Chicago medical clinic has admitted to making more than $500,000 by illegally selling opioid prescriptions to patients, according to the United States Department of Justice.

Prosecutors say the clinic owner, a doctor, and a physicians assistant illegally put close to a million illegal opioids and pills on the street.

Mohammed Shariff, who owned Midtown Medical Center in Chicago’s Uptown neighborhood, pleaded guilty to one count of conspiracy to knowingly dispense controlled substances outside the usual course of professional practice and without legitimate medical purpose. He could face up to 20 years in prison and a fine of up to $1 million.

Shariff, 68, conspired with a physician to sell oxycodone, hydrocone and other medications to patients they knew had no medical reason for taking the drugs, according to a plea agreement filed Tuesday in U.S. District Court in Chicago.

People wait outside Midtown Medical Center to purchase opioid prescriptions (U.S. Attorney’s Office)

The agreement states that from February 2012 to March 2013 Shariff and the physician, Dr. Theodore Galvani, received a total of at least $584,188 through the scheme. Shariff admitted to personally keeping at least $292,094 of the proceeds.

In the agreement, Shariff admits the two were responsible for illegally prescribing more than two kilograms of oxycodone, more than 595,0000 hydrocodone pills, and more than 190,000 alprazolam pills, commonly known as Xanax.

Shariff says people paid $100 to $200 in cash to Shariff and Galvani in exchange for the improper prescriptions. For those insured by Medicare, the two prescribed the opioids and then submitted false Medicare claims.

Galvani often saw more than 70 patients in a day, sometimes seeing them in groups of two or more at the same time, according to the agreement.

“I went inside the clinic, and it was filled with people. And as I tried to get toward the front counter, someone offered me a drug deal,” said 46th Ward Alderman James Cappleman.

That offer, the clamoring crowds, and constituent concerns prompted Capplement to take a video in 2012, which he gave to authorities. Little did he know then that it would be used in a federal investigation that ended Tuesday when Shariff pleaded guilty.

People wait outside Midtown Medical Center to purchase opioid prescriptions (U.S. Attorney’s Office)

Shariff’s guilty plea comes after his federal trial last spring ended in a hung jury.

“I was asked to testify. Actually I was ordered to testify in court last spring, and I did that,” Cappleman said. “It was a huge, huge change in the area. It was very noticeable right away as soon as that clinic closed down.”

Galvani, of Spring Grove, previously pleaded guilty to drug conspiracy charges and is awaiting sentencing.

In the plea agreement, Shariff also admitted he attempted to carry out a separate fraud scheme involving a home health care company that he owned, Elgin-based Home Health Resource LLC. In a meeting in May 2016 in Chicago, Shariff offered to pay an unidentified physician $500 each time the doctor certified patients with Medicare as eligible for home health care and referred the patient to Shariff’s company.

However, that doctor was cooperating with law enforcement and secretly recording conversations with Shariff. During their meeting Shariff said he arranged for his home health company to hide the fact that their clients were not truly eligible for those services.

Shariff told the physician that he instructed nurses at the company to “tell the patient you are homebound,” and that “when the doctor come, don’t say that you go out and drive and this and that. Don’t tell anybody you drive, don’t tell anybody you’re taking the bus, even going to the grociers. If anybody asks, ‘I stay home. I’m homebound.’”

Shariff’s sentencing is scheduled for March 19, 2019.