MIAMI (Reuters) - The top two officials of a leading chain of community mental health centers were among four people arrested in Miami on Thursday in connection with a scheme involving about $200 million in fraudulent medical claims, U.S. prosecutors said.

The four conspired to charge Medicare, the federal health insurance plan for the elderly and disabled, for mental health services that were either unnecessary or never provided to patients, according to the U.S. Attorney’s Office for the Southern District of Florida.

The arrested were: Lawrence Duran, owner of American Therapeutic Corp; Marianella Valera, chief executive officer of the company; and two other senior employees of American Therapeutic. The company is among the nation’s largest chain of community mental health centers licensed by Medicare.

They were charged in a 13-count indictment with conspiracy to defraud the United States and to receive healthcare kickbacks and to pay healthcare kickbacks.

The indictment alleges American Therapeutic and its senior employees conspired to bill Medicare for group therapy sessions for patients in assisted-living facilities, many of whom suffered from Alzheimer’s disease or other severe dementia.

The assisted-living facilities allegedly received kickbacks for the referrals to American Therapeutic.

The Medicare fraud described in the indictment was even bigger than that of an Armenian-American crime group charged in New York last week with operating phantom healthcare clinics that tried to cheat the federal program out up to $163 million.

U.S. authorities had touted the New York case as “the largest Medicare fraud scheme ever perpetrated by a single criminal enterprise.”

Miami and south Florida have long been considered a key region for fraud targeting healthcare programs for seniors because so many elderly Americans retire to live in the area.