The NYPD announced today that two letters mailed to Mayor Mike Bloomberg tested positive for the deadly toxin ricin.

The letters indicate the sender’s political disagreement with Bloomberg’s gun control position.

The anonymous threats to Bloomberg were opened in New York City on Friday, and by the director of the group Mayors Against Illegal Guns - of which Bloomberg is co-chairman - on Sunday.

Preliminary tests on both letters concluded that they contained the deadly toxin ricin, police said.

The writer of the letters made reference to debate on gun laws. Mayor Bloomberg is a strong supporter of gun control.

A law enforcement source told CBS News that the letter threatened ‘this is a taste of what’s to come if you come to take my gun,’ though the exact wording of the letter was not disclosed.

“The FBI has an investigation ongoing and so things like the exact wording and the postmarks, etc. we’re not going to disclose,” NYPD deputy commissioner Paul Browne told WCBS 880 and 1010 WINS. “It was a pink-orange oily substance that subsequently, in the preliminary tests, indicate the presence of ricin.”

This is an explicit case of domestic terrorism and the political nature of the letter further solidifies the fact that the person behind the letter intended to do harm to Bloomberg and/or cause Bloomberg to reconsider his gun control position.

It’s domestic terrorism with a side-dose of attempted assassination.

Several people who were exposed to the letter initially appeared asymptomatic, but an ESU officer who responded appeared to have minor symptoms that have abated (the toxicity is in the dose).

Civilian personnel in New York and Washington who came in contact with the opened letters remain asymptomatic, officials said. However, members of the NYPD Emergency Service Unit who came in contact with the letter that was opened at the city’s mail facility on Gold Street in Manhattan on Friday are being examined for minor symptoms of ricin exposure that they experienced on Saturday, which have since abated.

The person behind this, if the tests are confirmed, has engaged in multiple federal and state crimes, including use of weapon of mass destruction under 18 USC 2332a, attempted murder, and their New York State equivalents.

The letter was mailed from Shreveport, Louisiana.