When Dzhokhar Tsarnaev was indicted on 30 counts related to the Boston Marathon bombings, Carlin was a key part of the Justice Department's prosecution effort. The Tsarnaev case marked Carlin's biggest challenge since assuming the helm of the National Security Division on an acting basis in March after his predecessor, Lisa Monaco, joined the White House as a counterterrorism adviser. But Carlin is well suited to the job, having served as Monaco's chief of staff as well as the senior deputy in the division since moving over from the FBI in 2011, where he was Director Robert Mueller's chief of staff. Carlin, 40, has ascended rapidly within the Justice Department since graduating from Harvard Law School in 1999. Among his cases as an assistant U.S. attorney for the District of Columbia was the prosecution of Mitchell Wade, a defense contractor sentenced for bribing former Rep. Randall "Duke" Cunningham, R-Calif. Carlin served as national coordinator of DOJ's Computer Hacking and Intellectual Property Program, overseeing prosecutors trained to handle cybercrime and intellectual-property cases. Recently, he suggested that the department will be more aggressive in trying to bring criminal cases against state-sponsored cyberthreats. Carlin obtained his undergraduate degree from Williams College. He grew up in New York City, the son of an attorney and a poet. His mother teaches creative writing and Shakespeare at the New School in Manhattan.