Deadly bean: why ricin is used for bioterror

There was scarcely time to process the fatal Boston Marathon bombings on Monday when the news broke late yesterday afternoon that a letter mailed to Republican Senator Roger Wicker had tested positive for ricin, one of the most potentially toxic and easily-synthesized poison substances in the world, which is extracted from beans of the commonly available castor plant. Recent reports indicate that other letters mailed to other government officials, including President Obama himself, may have tested positive for ricin as well.