Letters containing ricin sent to New York mayor

The FBI and the New York City Police Department are investigating anonymous threatening letters recently sent to New York City Mayor Michael Bloomberg that tested positive for deadly ricin.

One letter arrived in New York on May 24 while the other arrived two days later in Washington at the offices of Mayors Against Illegal Guns. Both letters referenced the debate on gun laws. Bloomberg is a co-chairman of the coalition, Bloomberg reports.

Paul Browne, a spokesperson for the NYPD, said the NYPD's Intelligence Division and the FBI's Joint Terrorism Task Force are investigating the threatening letters. Civilian personnel who came into contact with the letters at both locations did not display symptoms. Members of the NYPD's Emergency Services Unit who had contact with the letters are being treated for minor symptoms of ricin exposure.

According to the U.S. Centers for Disease Control and Prevention, ricin, which is made from castor beans, can be fatal if ingested or inhaled.

In April, a man from Tupelo, Miss., was arrested in connection with mailing letters containing ricin to President Barack Obama and Sen. Roger Wicker (R-Miss.). James Dutschke was arrested on April 27 and charged with producing a biological agent for use as a weapon, Bloomberg reports.