Officials at the U.S. Capitol’s offsite mail facility on Tuesday discovered an envelope that tested positive for the deadly substance ricin. Its intended recipient was U.S. Sen. Roger Wicker (R-MS).
Law enforcement officials have been on high alert since Monday’s bombing at the Boston marathon, but there has been no indication that the two events are related. Sen. Claire McCaskill (D-MO) told Politico that the letter came from a source who frequently writes to members of Congress, and Sen. Mary Landrieu (D-LA) reports that the suspect is in custody.
CNN describes ricin as “a highly toxic substance derived from castor beans. As little as 500 micrograms — an amount the size of the head of a pin — can kill an adult.”
At least one more letter testing positive for ricin was discovered on Wednesday morning — Fox News reports that a second letter “contain[ing] similar language” and “signed identically” was mailed to President Obama, while ABC reports that a second letter was found at the U.S. Senate.
After complaints of a suspicious package outside of Sen. Richard Shelby’s (R-AL) office around 11:00 on Wednesday, Capitol police have detained someone found with a backpack full of letters in one of the Senate office buildings.