Officials say the ricin-laced letters sent to Mayor Bloomberg and the offices of his gun control group in Washington, DC are similar to one intended for President Obama.

On Thursday, New York Police Commissioner Ray Kelly said all three letters are simply addressed to "you."

“The letter in essence complains about gun control and says that anyone that comes for my guns will be shot in the face," he said.

Kelly says the letter addressed to Mayor Bloomberg was discovered as part of a routine letter screening process. The Mayor visited the mail room on Thursday to thank the workers for their efforts during the incident. Officials say employees there are no longer at risk for contamination.