Growing a New York team of former prosecutors, Bracewell & Giuliani has hired Glen Kopp, who served the past five-and-a-half years as an assistant U.S. Attorney in the Southern District. Kopp, 38, is joining as a nonequity partner who will work on white-collar defense, internal investigations and regulatory enforcement matters.

At the U.S. Attorney’s office, Kopp led investigations and prosecutions in cases involving fraud, terrorism, national security, hostage taking and narcotics and weapons trafficking. He prosecuted a former Mexican governor for conspiring to launder millions of dollars of illegal drug proceeds and led the case against Manssor Arbabsiar for plotting to assassinate the Saudi Arabian ambassador to the United States. He was on the team that prosecuted 10 Russian agents who were part of a 2010 spy swap deal between the United States and Russia.

Kopp said that when one leaves the U.S. Attorney’s office, the fear is that no cases will ever be as good or interesting. But Bracewell’s cases attracted him, and “I wouldn’t be disappointed,” he said.

“We’ve been consumed with jury trials and complex investigations all around the country in the last couple of years and Glen is the kind of first-rate lawyer we want in those serious cases,” said partner Marc Mukasey, also a former assistant U.S. attorney in the Southern District, in a statement.

The Houston-based firm is representing Dr. Sidney Gilman, a witness in the insider trading case against a former trader of SAC Capital. The firm represented Halliburton in the federal criminal investigation that arose from the Deepwater Horizon explosion.

Kopp, who said he spoke with several firms, was also attracted to Bracewell’s growth prospects. The firm’s New York office has about 70 lawyers.