Following the discovery of a letter bomb in the Deutsche Bank mailroom, the NYPD issued a warning to New York banks that they concentrate their security efforts on mailrooms.  The suspicious package containing a letter bomb, which Deutsche Bank confirmed receiving, was addressed to CEO Josef Ackermann of Deutsche Bank in Frankfurt, Germany.  The bomb did not detonate and no one was injured. NYPD Warning. The warning to bank security officials reads in part: "We have received a report of a confirmed mail (package) explosive device that was addressed and sent to ... Deutsche Bank in Frankfurt, Germany.  The package was detected by X-ray technology inside the mail room. The package did not detonate." NYPD officials stepped up security around Deutsche Bank locations in New York City.  There was no immediate word on what individual or what group sent the apparent letter bomb. The FBI issued a statement saying that its joint terror task force is "working with German authorities to assess the incident in Frankfurt and any potential threat to facilities or people here."  The FBI added that "there is no specific threat to New York associated with the incident at this time."   [NBCTV, 12/7/11]