(CNN) -- A suspicious letter addressed to President Barack Obama intercepted Thursday in the Washington area appears to be connected to possibly poison-laced notes sent to New York Mayor Michael Bloomberg and an anti-illegal-gun group he founded, a law enforcement official said.
The official did not know the status of any testing on anything found in the letter and did not disclose any details about whether there was a message in the letter. The source said the letter appears similar to the notes sent to the mayor and his group, Mayors Against Illegal Guns.
The letter to Obama was spotted at the White House off-site mail sorting facility and never made it to the White House, said the source who had been briefed on the investigation. The FBI was alerted this morning and is investigating.
Preliminary tests sent to Bloomberg and his group indicate ricin was found in the letters, New York deputy police commissioner Paul Browne said Wednesday.
One of the letters addressed to the mayor's office was opened at the city government's mail facility. The second letter to the mayor was opened by Mark Glaze, director of Mayors Against Illegal Guns, in Washington on Sunday.
Suspected ricin has been included in letters in the past few months sent to Obama and other officials. In April, letters were sent to Obama; Sen. Roger Wicker, R-Mississippi; and Sadie Holland, a judge in Lee County, Mississippi. James Everett Dutschke of Tupelo, Mississippi, has been charged with possession and use of a biological agent in connection with the case.
If inhaled, injected or ingested, less than a pinpoint of ricin can kill a person within 36 to 48 hours because of the failure of the respiratory and circulatory systems. There is no known antidote for the toxin, which is derived from castor beans.