NEW YORK (CBSNewYork) — Twenty-three people have been charged in an alleged Medicaid fraud ring that preyed on the city’s poor, Brooklyn District Attorney Kenneth Thompson said Tuesday.

Thompson said recruiters would stake out homeless shelters, soup kitchens and welfare offices searching for people with Medicaid cards. The recruiters would then allegedly offer them free sneakers if they boarded a van and went to one of several clinics to undergo a battery of unneeded tests. The customers would also be given items such as orthopedic insoles and knee braces that were medically unnecessary.

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The clinics would then bill Medicaid for the services and medical products, Thompson told reporters, including WCBS 880’s Alex Silverman.

The enterprise fraudulently billed for more than $6.9 million over two years, the DA said.

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“Particularly egregious because it could not have succeeded were it not for the exploitation of poor people who needed shoes,” Thompson said.

Thompson said the ringleader was Eric Vanier, 43, of Manhattan, who owned or was affiliated with eight clinics and was caught on a wiretap referring to the patients as “guinea pigs.” His mother Polina Vainer, 66, of Staten Island, allegedly served as his second in command.

Nine doctors are among the 23 people charged. The charges include enterprise corruption, money laundering, scheme to defraud, health care fraud and grand larceny.

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The top charge in the case carries with it a 25-year maximum prison sentence, 1010 WINS’ Kevin Rincon reported.