A Texas woman has been placed under arrest in connection with the poison-laced letters sent to President Barack Obama and Mayor Michael Bloomberg last month, an FBI spokesman tells NY1.
Federal authorities have identified the woman as Shannon Richardson of New Boston, TX.
A ricin-laced letter was also sent to the mayor's gun control group, Mayors Against Illegal Guns.
The letters were all post marked May 20 and sent from Shreveport, Louisiana.
The letters contained a threatening message focused on the guns saying, "You will have to kill me and my family before you get my guns."
Mayor Bloomberg did not personally come into contact with the ricin.
The poison can be deadly when ingested or inhaled.
Police Commissioner Ray Kelly had said at the time that it appeared all of the letters were sent by the same person.
Earlier this month, FBI agents search a home in New Boston, Texas as part of the investigation into the letters.
In a statement, Mayor Bloomberg thanked investigators, adding," City and Federal agencies worked collaboratively from the outset and will continue to do so as the investigation continues."
Police Commissioner Ray Kelly also praised investigators in a statement, adding, "Fortunately, neither Mayor Bloomberg, President Obama, the director of the Mayors Committee Against Illegal Guns, nor those who processed the ricin-laced mail incurred serious illness or injury, in part because of safety measures already in place."