
Federal authorities continue ricin investigations —
President Barack Obama salutes as he returns to the White House after a trip to Chicago on Thursday, May 30. Federal authorities searched the home of a Texas man on Friday in connection with an investigation into threatening letters, possibly tainted with ricin, that were sent to Obama.

Federal authorities continue ricin investigations —
New York Mayor Michael Bloomberg also was recently sent threatening letters, possibly tainted with ricin.

Federal authorities continue ricin investigations —
In April, Sen. Roger Wicker of Mississippi was sent a suspected ricin-laced letter.

Federal authorities continue ricin investigations —
James Everett Dutschke speaks with the media as federal authorities search his Tupelo, Mississippi, home on April 23, in connection with several suspected ricin incidents. Dutschke was later charged with possession and use of a biological agent in connection with a ricin-tainted letter sent to Sadie Holland, a judge in Lee County, Mississippi.

Federal authorities continue ricin investigations —
Bulgarian dissident Georgi Markov died in London in 1978 after being hit by a ricin-filled dart that was fired from an umbrella. He is the only person known to have been killed in a ricin attack.

Federal authorities continue ricin investigations —
This tiny, ricin-tainted platinum ball killed Markov, who also was a broadcaster for the BBC.

