U.S. federal prosecutor Ronald Cheng has rejoined O’Melveny & Myers as a partner in the firm’s white collar defence and corporate investigations group.

Cheng, who will be based in O’Melveny’s Hong Kong and Los Angeles offices, was an associate at the firm in the early 1990s. He then spent 20 years as a federal prosecutor, serving in a number of roles at the Department of Justice, including chief of the Criminal Appeals Section and chief of the Criminal Division of the U.S. Attorney’s Office, and legal advisor to the U.S. Embassy in Beijing.

He is also a former member of the Cybercrime and Intellectual Property Crimes Section of the U.S. Attorney’s Office for the Central District of California.

Cheng’s return to O’Melveny strengthens the firm’s capability in three key areas, said Bradley Butwin, the firm’s chairman, in a statement.

“He increases our ability to serve clients in matters involving US-Chinese law enforcement, he adds to our bench of seasoned, versatile Southern California litigators, and he brings additional firepower to our global data privacy and cybersecurity capabilities.”