Justice Department officials have charged at least four people in connection with schemes to defraud Tricare as part of a larger fraud "takedown" that resulted in charges against 412 people involving $1.3 billion in taxpayer dollars.

It's the department's largest health care fraud enforcement action ever, according to Justice officials. The Defense Criminal Investigative Service was one of several agencies involved in the effort, which was spearheaded by the Medicare Fraud Strike Force.

The charges, announced Thursday by Attorney General Jeff Sessions and Department of Health and Human Services Secretary Tom Price, accused the 412 defendants of allegedly participating in schemes to submit claims to Medicare, Medicaid and Tricare for treatments that weren't medically necessary, and often were never provided. 

Of the 412 people charged across 41 federal districts, 115 were doctors, nurses and other licensed medical professionals. 

In one Florida case, a defendant was accused of falsely representing himself to be a "retired lieutenant commander of the U.S. Navy Submarine Service," according to a Justice Department news release. He allegedly made this false claim to gain the trust and personal information from Tricare beneficiaries, many of whom were military members and retirees, for use in a fraudulent billing scheme. 

In another case investigated by the Southern Louisiana Strike Force, a pharmacist was charged with submitting and causing the submission of $192 million in false and fraudulent claims to Tricare and other health care benefit programs for dispensing compounded medications that were not medically necessary, and were often based on prescriptions originating from illegal kickback schemes. Information was not immediately available about how much of that $192 million involved Tricare.

"Our enforcement actions underscore the commitment of the Defense Criminal Investigative Service and our partners to vigorously investigate fraud perpetrated against the DoD's Tricare program," said Kelly P. Mayo, deputy DCIS director, in the announcement. "We will continue to relentlessly investigate health care fraud, ensure the taxpayers' health care dollars are properly spent, and endeavor to guarantee our service members, military retirees, and their dependents receive the high standard of care they deserve."

The Medicare Fraud Strike Force is a partnership between the Justice Department's criminal division, U.S. attorney's offices, the FBI and the HHS Office of Inspector General. 

In 2016, the task force charged 301 people in a nationwide sweep, alleging $900 million in fraud.

Senior reporter Karen Jowers covers military families, quality of life and consumer issues for Military Times. She can be reached at kjowers@militarytimes.com.