A threatening letter was mailed to President Obama that is similar to two letters containing poisonous ricin sent to Mayor Bloomberg and his anti-gun group, officials confirmed Thursday.
The letter, first reported by NBC 4 New York, is being tested for ricin. It was received Wednesday at an off-site facility, and did not reach the White House, according to the Secret Service.
"This letter has been turned over to the FBI Joint Terrorism Task Force for testing and investigation," said Brian Leary, a Secret Service spokesman.
The text of that mailing was identical to the letters sent to the mayor and his gun group, which threatened: "what's in this letter is nothing compared to what I've got planned for you," police and law enforcement sources said.
One letter was discovered at City Hall's mail sorting facility at 100 Gold St. on Friday, a law enforcement source told NBC 4 New York. It appeared to contain a pink, oily substance when a mail worker came across it and was immediately flagged as suspicious.
An initial field test didn't bring up any sign of ricin, a source said. But more preliminary testing Wednesday showed the letter tested positive for ricin.
An identical letter containing ricin was sent to the Mayors Against Illegal Guns headquarters in Washington, D.C. and was opened on Monday, police said.
The mailings put New York City officials on edge; Police Commissioner Ray Kelly said other suspicious letters were investigated at downtown locations, including two at the office of the city's public advocate, who is a Democratic mayoral candidate, and another near City Hall. Those were said to be unrelated to the ricin scare.
According to law enforcement sources, the three similar threatening letters were postmarked May 20 in Shreveport, La. and sent without a return address or signature. Sources said the NYPD tried to pull fingerprints off the letter discovered at the city's mail sorting site, but nothing usable was found. Authorities also plan to check for any possible DNA.
It wasn't known if any viable forensic evidence was discovered on the letters sent to Washington or the White House. All three mailings read in part: "You will have to kill me and my family before you get my guns. Anyone wants to come to my house will get shot in the face. The right to bear arms is my constitutional God given right and I will exercise that right till the day I die."
Bloomberg is the founder of the anti-gun group and has emerged as one of the country's most potent gun-control advocates, able to press his case with both his public position and his private money.
On Wednesday, the mayor said he didn't know what pushed whoever sent the ricin-laced letters to do so, but that his anti-gun efforts would not be deterred, despite the threats in the letter addressed to him.
"There's 12,000 people that are going to get killed this year with guns and 19,000 that are going to commit suicide with guns, and we're not going to walk away from those efforts," said Bloomberg, adding that he didn't "feel threatened."
Civilian workers who came into contact with the letters have not shown symptoms of being poisoned by the ricin, police said. Some members of NYPD's emergency service unit who did come into contact with the opened letter in New York initially showed some minor symptoms of ricin exposure, but the symptoms have since abated.
Bloomberg visited mailroom employees Thursday and thanked them for their service, a spokesman said.
According to the Centers for Disease Control, ricin is a poison found naturally in castor beans. Symptoms can include difficulty breathing, vomiting and redness on the skin depending on how the affected person comes into contact with the poison.
Police said the letter sent to the anti-gun group was opened by Mark Glaze, the director. He was working out of the offices of The Raben Group, a Washington lobbying firm where he keeps an office.