(CNN) Maria Zapata went to see Dr. Jorge Zamora-Quezada a little more than five years ago because one of her knees was bothering her. The rheumatologist told her that she had arthritis and that he'd give her injections "to strengthen the cartilage" in her knee, she said.

Her husband asked, "Why are you giving her so many injections?" The doctor reassured them that the treatment would help.

But Zapata, 70, of McAllen, Texas, said the medication didn't help and might have been making things worse: There was discoloration on her legs. Other doctors raised concern about the treatments, and her family doctor even told her she didn't have arthritis.

Zapata was not the only patient given treatment she might not have needed, according to a joint federal and local investigation.

A task force investigating Zamora-Quezada announced Monday that he was being indicted in a fraud case involving $240 million in claims that were in part based on "fraudulent statements" to be submitted to health care benefit programs, resulting in $50 million paid to the doctor.

The news spread fast. Worried patients who were cared for at his Brownsville, Edinburg and San Antonio clinics expressed concern on Facebook; others shared stories about how their mothers, grandmothers and children were treated.

The Department of Justice said Monday that the rheumatologist had given patients chemotherapy and toxic treatments they didn't need, all to fund his "lavish" and "opulent lifestyle."

One of the expensive properties investigators say Zamora-Quezada bought.

"Today's indictment is the first step in holding Dr. Zamora-Quezada accountable for his allegedly egregious criminal conduct," said C.J. Porter of the US Department of Health and Human Services Office of Inspector General's Dallas Region. "His patients trusted him and presumed his integrity; in return, he allegedly engaged in a scheme of false diagnoses and bogus courses of treatment and doled out prescriptions for unnecessary and harmful medications, all for his personal financial gain and with no regard for patient well-being."

The doctor, who is no stranger to the courts and had been publicly reprimanded by the Texas Medical Board in the past, was indicted Monday and accused of falsely diagnosing patients with various degenerative diseases including rheumatoid arthritis. The 61-year-old was charged with one count of conspiracy to commit health care fraud, five counts of health care fraud and one count of conspiracy to commit money laundering.

When contacted by CNN, a lawyer who has previously represented Zamora-Quezada said he has not represented the doctor in several years. Calls to Zamora-Quezada's numbers went unanswered.

According to the indictment, Zamora-Quezada would order a battery of "fraudulent, repetitive, and excessive medical procedures on patients in order to increase revenue."

When patients would question his procedures and diagnoses, he'd dismiss them from his clinic.

Nora Rodriguez, 44, said Zamora-Quezada kicked her out after she asked why all the medicines he prescribed hadn't worked. "He kept getting upset when I was asking him why I was feeling worse and not getting better," she said. "He yelled and told me, 'you are no longer my patient; get out of this office.' I'm getting chills remembering this."

When they would request their medical records, Zamora-Quezada would "conceal patient records from other rheumatologists," the indictment says.

The documents said he would even hide those records from Medicare in an insecure and dilapidated building in the Rio Grande Valley. Photos in the court documents show a pile of medical records haphazardly thrown across the floor of the building.

Court documents include photos of what may be patient records kept in an unsecure building.

The indictment also accuses Zamora-Quezada of being a part of an extensive international money-laundering scheme, saying he laundered money through a money exchange house, known as a casa de cambio, and sent it to various accounts in financial institutions in Mexico.

Not all of the money made it to the financial institutions, according to the indictment. The doctor lived large on his earnings. The Department of Justice is seeking the forfeiture of his million-dollar personal jet, a Maserati that had ZQ -- his initials -- painted on its exterior and several of his luxurious properties.

Zamora-Quezada owned a fleet of luxury cars and purchased numerous expensive commercial and residential properties, including two penthouses in Puerto Vallarta, Mexico; a condo in Aspen, Colorado; and one in Punta Mita, Mexico. He also owned multiple homes and commercial buildings in Texas, court records show.

In 2009, the Texas Medical Board publicly reprimanded Zamora-Quezada for conducting excessive tests without a legitimate basis, records show. Zamora-Quezada was also fined and put on notice by the board but continued to practice.

A doctor who had referred patients to Zamora-Quezada's practice seemed puzzled by some of his recommendations.

"Honestly, we didn't know that was going on there," said Dr. Magdalena Caudillo of Peñitas, Texas. "He would never deny any of our patients, even if we knew there was no major diagnosis."

She said her patients would often return to her office without consult notes from Zamora-Quezada and would often be prescribed the same things.

"I didn't think there was anything seriously wrong with you," Caudillo often would tell these patients, she said. "This isn't going to work. This isn't stuff that you need."

However, she said, some patients felt that the treatments did help.

Roselie Ibarra, now 19, said her pediatrician sent her to Zamora-Quezada in 2012. Her mom was worried because her knees would make a popping sound when she squatted down.

She said Zamora-Quezada diagnosed her with rheumatoid arthritis and said she had a slight scoliosis and was anemic. Ibarra felt out of place at the clinic, she said, because the waiting room was filled with older people.

The doctor prescribed vitamins, a pain patch and hydrocodone, and every time she was at the office, there were blood tests and X-rays. He gave her an injection only once, in her back, "but that was my first and last shot." He wanted to give her more, she said, but she refused. "I wasn't in pain and didn't feel like I needed them."

She left Zamora-Quezada's care in 2016, when she left for college. But when she moved to another state to join the military and had a followup with another doctor, they did not find any arthritis. She wonders now whether she ever was sick.

When Ibarra saw the news of the indictment Tuesday, she called the FBI victim hotline.

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The FBI is asking for other patients who were in the doctor's care between January 2000 and May 2018 to call the hotline at 1-833-432-4873, Option 8, or email ZamoraPatient@fbi.gov. The FBI is legally mandated to identify victims of federal crimes that it investigates and provide these victims with information, assistance services and resources.

This case is certainly not an isolated incident involving potential medical fraud. Health care fraud costs the country about $68 billion annually, according to estimates from the National Health Care Anti-Fraud Association , and that's probably a conservative number. That's about 3% of the $2.26 trillion the country spends on health care, according to the association.

"It makes me feel bad, because you go to a doctor trusting in them," former patient Zapata said. "I felt bad because he was practically inventing things."