After nearly six years at the U.S. Attorney’s Office for the District of New Jersey, Ray Mateo has rejoined Calcagni & Kanefsky as a partner in Newark, according to an announcement by the firm. He was added to expand the firm’s white collar criminal and regulatory defense and investigations practice, with a particular focus on the firm’s health care litigation and licensing focus.

As an assistant U.S. attorney, Mateo served as chair of the office’s Opioid Abuse Prevention and Enforcement Task Force, leading federal criminal prosecutions, from investigation to jury trial, of health care and other matters involving allegations of Medicaid and Medicare fraud, anti-kickback schemes, bank fraud, wire fraud, identity theft, tax evasion, money laundering, and distribution of controlled substances.