Jonathan Diesenhaus advises and advocates for companies and professionals in the life sciences, healthcare, and other regulated industries in civil, criminal, and administrative enforcement matters. Jonathan helps clients respond quickly and efficiently to government investigations, evaluating allegations, reviewing evidence, assessing risk, and identifying strategies to achieve the most appropriate results.

As a leading False Claims Act litigator, he defends qui tam cases brought by whistleblowers and the government in federal courts across the United States. Amid threats of prosecution and fines for retaining overpayments, even when there was no fraud, Jonathan guides his clients through internal investigations, repayment, and when necessary, voluntary disclosures to agencies and law enforcement. His clients include pharmaceutical and medical device companies, hospitals, physician groups, research universities, and academic medical centers.

Jonathan has been prosecuting and defending healthcare and government program fraud cases for over 25 years. From 1998 to 2005, he handled civil healthcare fraud, False Claims Act, and qui tam cases as a senior trial counsel in the Civil Division of the U.S. Department of Justice. He represented the government in matters that established the False Claims Act as a vehicle to pursue violations of the Anti-Kickback Statute, the Stark Law, and of the Food, Drug, and Cosmetic Act. Jonathan has received a number of awards for his work from the U.S. Department of Justice, the FDA, and the Office of Inspector General in the U.S. Department of Health and Human Services.

Jonathan also works with industry and academic trade associations to educate policymakers on the complications of prosecuting healthcare fraud under both state and federal qui tam statutes, on the detrimental impact of the qui tam and federal False Claims Act investigations, and the effect that litigation has on businesses and individuals.