In the biggest crackdown on fraudsters in the history of Medicare Task Force, U.S. federal investigators have charged 91 people, including doctors, nurses and clinic owners, for attempts to bilk the Medicare system.

The 91 people were charged in eight different cities for billing for services not provided, money laundering, threatening Medicare beneficiaries and providing kickbacks for beneficiary numbers.

From Brooklyn to Miami to Los Angeles, the defendants allegedly treated the Medicare program like a personal piggy bank, the head of the Justice Department's criminal division, Lanny Breuer, told reporters in Washington.

Among arrested was a Detroit doctor who allegedly billed Medicare for services provided to dead people. Seventy of the defendants were charged this week and 21 others were charged in recent weeks.

The biggest number of defendants came from Miami, where 45 were charged for false billing of $159 million for home healthcare, durable medical equipments, HIV treatment infusion and mental health services.

Two people were charged in Houston for false billing of $62 million.

Altogether, the 91 defendants are charged with attempting to bilk the system out of nearly $295 million.

The federal program, which caters to more than 40 million elderly and disabled Americans, has been bleeding billions to waste, fraud and abuse, according to healthcare experts and law enforcement.

In October last year, authorities arrested 52 Los Angeles area residents for their alleged roles in a nationwide scheme to bilk Medicare out of more than $160 million.

In 2008, criminals from two Florida counties alone accounted for approximately $400 million in fraudulent Medicare bills.