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Veteran DOJ Prosecutor Mark Chasteen Joins Varnum

April 28, 2025

Former White Collar Chief for Eastern District of Michigan Bolsters Firm’s Government Investigations and Compliance Offerings

Varnum is pleased to announce that Mark Chasteen, former Assistant U.S. Attorney for the Eastern District of Michigan, has joined the firm as a partner in its White Collar Defense and Government Investigations practice.

Chasteen brings 17 years of federal prosecutorial experience, most recently serving as Chief of the White Collar Crime Unit, as well as Deputy Chief of the Appellate Division and Violent & Organized Crime Unit. In his leadership role, Chasteen oversaw a team of 20 attorneys prosecuting complex matters involving health care fraud, bribery, money laundering, and other financial crimes. His work included investigations into fraudulent billing involving Medicare, Medicaid, and private insurance, as well as the illegal diversion of prescription drugs.

“We are thrilled to welcome Mark to the firm,” said Jon Bylsma, Chair of Varnum. “His background in leading high-stakes prosecutions, coupled with his deep understanding of regulatory enforcement, significantly enhances our capabilities in a key area of client need.”

Chasteen joins an accomplished team that has represented clients in some of the region’s most high-profile matters, including the defense of individuals in the Flint Water Crisis, service on the General Motors Ignition Switch Monitorship, and the independent investigation of the Oxford School Shooting. The team also routinely defends businesses and individuals in civil and criminal tax matters.

“Mark’s arrival is a major asset to our white collar and investigations team,” said Ron DeWaard, leader of Varnum’s White Collar Defense and Government Investigations practice. “His DOJ experience and trial-tested leadership will bring immediate value to clients facing scrutiny from federal agencies or State Attorneys General, as well as those seeking proactive guidance to reduce enforcement risk.”

Chasteen expressed enthusiasm about joining the firm and contributing to its strong platform in government investigations.

“I’m excited to bring my experience to Varnum and contribute to the firm’s strong reputation in white collar defense and government investigations,” said Chasteen. “This new role offers the opportunity to partner with businesses and Boards of Directors as they navigate investigations and enforcement actions brought by State Attorneys General, the DOJ, and other regulators.”

Chasteen earned his law degree from Yale Law School and his undergraduate degree from the University of Michigan.

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