A letter addressed to Mayor Bloomberg last week has tested positive for ricin, a lethal toxin that can kill in an extremely small dosage if inhaled. According to the NYPD, "anonymous threats to Mayor Michael R. Bloomberg in letters opened in New York City on Friday and by the director of the Mayors Against Illegal Guns in Washington, DC on Sunday contained material that when tested locally, preliminarily indicated the presence of ricin."

The writer of the letters threatened Bloomberg, and appears to be motivated by the mayor's efforts to pass stricter gun control laws. The NYPD says "civilian personnel in New York and Washington who came in contact with the opened letters remain asymptomatic. However, members of the NYPD Emergency Service Unit who came in contact with the letter that was opened at the city’s mail facility on Gold Street in Manhattan on Friday are being examined for minor symptoms of ricin exposure that they experienced on Saturday but which have since abated."

Bloomberg never received the letter sent to him, which was addressed to 100 Gold Street, where the offices of the Department of Housing Preservation and Development are located. Both letters were postmarked in Shreveport LA on May 20th. According to the American Postal Workers Union, "the substance involved was not in a form that could be inhaled or otherwise readily ingested."