(CNN) — Preliminary tests indicate ricin was found in letters sent this past weekend to New York Mayor Michael Bloomberg and the director of Mayors Against Illegal Guns, New York deputy police commissioner Paul Browne said Wednesday.
Browne said the letter to Bloomberg contained a threat to the mayor and referenced the debate on gun laws.
Some of the emergency services workers who touched the letter are being examined after they showed minor symptoms of ricin exposure on Saturday, he said. The symptoms have since subsided.
Civilian workers showed no symptoms, Browne said.
Another threatening letter was opened by Mark Glaze, the director of Mayors Against Illegal Guns, in Washington on Sunday.
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