How do forensic scientists pinpoint sources of deadly agents like ricin?

Federal authorities have arrested a suspect accused of sending letters laced with the deadly toxin ricin to representatives on Capitol Hill and to President Barack Obama. C&EN has extensive reporting on ricin in the magazine’s archives. The stories cover how ricin is made, how it works as a toxin in people, how it can be detected and defused, and its structural and other characteristics. Ricin is the only substance to be banned under both the Chemical and Biological Weapons Treaties. C&EN will report on the current situation in Washington, D.C., as events warrant and as more information becomes available.