The former chief of the Southern District U.S. attorney’s public corruption unit has left for private practice. The prosecutor, Daniel L. Stein, is joining Richards Kibbe & Orbe as a partner effective March 28 as a member of the securities enforcement and criminal defense practice group.

Brendan McGuire will be the new head of the public corruption unit. Mr. McGuire, who has been with the office since 2005, has had several major cases during his time in the terrorism and international narcotics unit, including the prosecution of Times Square Bomber Faisal Shazad, Somali pirate Abduwali Muse and Syrian arms dealer Monzer al Kassar. His deputy chief will be Michael Bosworth, who has been with the unit since 2009. Mr. Bosworth was part of the teams that prosecuted the cases of ex-NYPD Commissioner Bernard Kerik and former City Councilman Larry Seabrook. He is now involved in the prosecution launched last week against state Senator Carl Kruger and seven others.