Who Investigates Medicare Fraud: CMS, OIG, DOJ and the Civil-Criminal Divide

The Centers for Medicare & Medicaid Services and its contractors, the HHS Office of Inspector General, the FBI and the Department of Justice investigate Medicare fraud, with different powers over payments and cases. If you work in billing, clinical care, pharmacy operations or finance, you may see a false order, an altered record or a payment that kept arriving after someone raised a concern. False claims take money meant for patient care. The agency names tell you who can act. Your knowledge can explain what happened inside the business.

The Payment Trail Explains Who Gets Involved

Original Medicare claims pass through private Medicare Administrative Contractors working for the Centers for Medicare & Medicaid Services. Enrollment establishes who can bill. The order and clinical record describe the service, the claim requests payment, the remittance records the payment decision, and bank records identify who received the money.

Part D adds a pharmacy claim handled through a plan or pharmacy benefit manager, followed by the sponsor’s drug-event data, rebate reporting and reconciliation with CMS. Medicare Advantage, Part C, uses advance monthly payments to plans and risk-adjustment information. A plan’s payment to a provider and CMS’s payment to the plan are separate transactions.

The Congressional Research Service described the structural problem in its 2011 report on Medicare program integrity: pressure to pay claims quickly had created a pay-and-chase approach. Contractors processed payments while other contractors developed suspected fraud cases for investigators. That separation explains why the payment file and the account from someone inside the business matter together.

Who Is Responsible for Medicare Fraud?

Responsibility for a false Medicare claim can reach the person who knowingly submits it or causes it to be submitted. A clinician may supply the order, a billing agent may transmit the claim, and an owner may control the bank account. We connect that Medicare fraud evidence to the decisions behind the payment. The person pressing submit may be following someone else’s instructions.

What CMS and Its Contractors Do

CMS administers Medicare and uses contractors for claims processing, medical review, payment-error measurement and fraud investigations. The contractor’s assignment tells you what its review is trying to establish.

CMS’s Medicare Administrative Contractor description explains the claims administrator’s role. Its fraud-investigation contractors develop leads and recommend action. CMS and the claims contractors implement the relevant payment and enrollment decisions. Knowing which contractor wrote a notice helps us connect it to the underlying claims and the business’s response.

What Claims Analytics Can Show

Claims analytics can identify unusual billing and point investigators toward records worth examining. The next work is concrete: checking the order, the service, the payment and the people who made the decisions.

A study published by the Association for the Advancement of Artificial Intelligence in 2018 tested machine-learning models using Medicare payment data and provider exclusions. It found decision-tree and logistic-regression models performed best among the models it tested. The study also explains a limitation that disappears in confident talk about automated fraud detection:

The study created those labels by matching providers to OIG’s exclusion list. Its claims data had been aggregated by provider, service code and place of service after payment. An employee’s account can add the decision behind a pattern: who changed the record, what they were told to change and why.

The whistleblower’s complaint against Strauss Ventures, which operates as The Grand Health Care System, alleged exactly that kind of hidden work:

In the complaint’s telling, the reimbursement target decided how much therapy the record said happened. We see billing targets standing in for patient care. The original notes, later changes and instructions to staff can explain how a billing pattern was produced.

What HHS-OIG and the FBI Investigate

The Department of Health and Human Services Office of Inspector General and the FBI investigate suspected healthcare fraud through claims and financial analysis, interviews and other investigative tools. Their work can connect clinical records to ownership, communications and the movement of money.

HHS-OIG also has administrative powers. It can exclude providers from federal health care programs, pursue civil monetary penalties and negotiate corporate integrity agreements. Exclusion is separate from CMS revoking a provider’s Medicare enrollment.

An OIG corporate integrity agreement creates continuing oversight obligations. Those can include training, independent review, reporting and overpayment disclosures. For someone working in compliance, the agreement can make the company’s later reports and review findings especially revealing.

CMS has its own payment power. It can hold payments on a credible fraud allegation while the investigation continues. A payment hold tells us what happened to the money. The investigation still has to establish what happened behind the claim.

Criminal Investigation Versus Civil Medicare Case

Criminal investigations examine suspected crimes, while civil Medicare cases under the False Claims Act seek recovery for false claims. The Justice Department’s civil attorneys and civil teams in U.S. Attorneys’ Offices pursue those civil matters, including cases started by whistleblowers. Criminal prosecutors work with investigative agencies to pursue criminal charges.

The Justice Department’s policy on parallel proceedings provides for coordination among criminal, civil, regulatory and administrative work. A decision against criminal prosecution leaves the civil question open. For an insider, the useful account connects the payment representation to who directed it and what the business knew.

The Justice Department’s April 7, 2026 memorandum directed the National Fraud Enforcement Division to take operational control of the Health Care Fraud Unit and called for a Civil Division liaison. The August 18 organizational rule, effective August 24, 2026, formally established the division and assigned it criminal health care fraud responsibilities.

What Is the Medicare Fraud Strike Force?

The Medicare Fraud Strike Force is a coordinated enforcement model bringing together federal prosecutors, HHS-OIG, the FBI, CMS and other investigative partners. Its work combines data analysis with investigations across the country. The Justice Department’s Health Care Fraud Section and U.S. Attorneys’ Offices coordinate criminal cases within that network.

The network also addresses other public and private health care payers. A national health care fraud announcement can therefore contain Medicare cases, Medicaid cases and other insurance cases, as well as separate civil and administrative actions.

What Happens When OIG Declines a Referral?

A Unified Program Integrity Contractor’s case can continue after the Inspector General declines the referral. CMS’s Program Integrity Manual expressly tells the contractor not to close a case simply because OIG’s Office of Investigations did not accept it.

Before referral, the contractor develops the lead and corroborates the concern through work such as beneficiary interviews and billing review. After a declined referral, the manual provides for other administrative action and possible resubmission.

That matters when someone inside a business hears that the government passed on a case. Which office made the decision, and what was it deciding? OIG’s response to a contractor referral and the Justice Department’s decision about joining a civil whistleblower case are separate decisions. We examine the actual response alongside the underlying conduct and the claims that followed it.

Does an Indictment Prove a Company Committed Fraud?

No. An indictment states criminal charges.

The Operation Gold Rush criminal indictment alleged that organizers bought durable medical equipment companies already able to bill Medicare, installed nominal owners and concealed who controlled them. It charged that the businesses used stolen identities to bill for equipment patients had never received. Beneficiaries then complained about unfamiliar suppliers and doctors they had never visited.

That alleged scheme crossed enrollment, billing, delivery and banking. The indictment gives an insider specific conduct to recognize: the person on the ownership paperwork, the person directing the business and the person controlling the money could tell different stories.

Is Stopped or Seized Money the Same as Money Returned to Medicare?

No. Payment prevention, seizure and money returned to Medicare are separate events. In its 2025 annual review, the Justice Department said HHS-OIG and CMS prevented the Gold Rush organization from receiving all but $41 million of the $4.45 billion scheduled for Medicare payment.

Stopped before it left Medicare. That is the point of following the payment, not just the announcement.

Is Medicare Fraud the Same as Medicaid Fraud?

No. Medicare and Medicaid fraud involve different programs, even when investigators examine the same provider. Medicare is federal. State Medicaid Fraud Control Units investigate Medicaid matters and can participate with federal agencies in joint cases.

State authorities and private insurers can contribute evidence, referrals and their own payment interests. Their participation helps explain why several agencies appear in one announcement. The claims and payment records identify which program or insurer paid for the conduct being examined.

Medicare Fraud Tip Referral Agencies and the Whistleblower’s Case

Medicare fraud tip referral agencies include CMS, HHS-OIG and the FBI, with additional integrity channels for Medicare Advantage and drug-plan matters. A tip supplies information to an agency. It does not itself start a qui tam case under the False Claims Act.

We work with insiders to connect what they know to the business’s claims and payments, and bring in Medicare fraud whistleblower lawyers for the civil case. The agency map helps us understand an existing inquiry, a contractor referral or a continued payment after a warning. You can start that conversation with the part of the business you know.

A whistleblower case under the False Claims Act can pay 15% to 30% of what the government recovers.

You Know What Happened Behind the Claim

If you saw records altered, instructions ignored or billing continue after a concern reached management, speak with our whistleblower experts about the decisions behind those Medicare payments. We build the case with you and bring in Medicare fraud whistleblower lawyers who understand the payment system and the agencies involved. We stay beside you from that first account through the case.