THE search has begun for the ricin attacker. On 2 February, an aide to Republican Senate leader Bill Frist alerted security to an unusual amount of dust on a mail-opening machine. It proved to contain ricin, a deadly poison found in castor beans.
It is not clear how long the loose powder had lain on the machine, but it is thought to have arrived in the mail. According to the US Centers for Disease Control and Prevention, inhaling just 500 micrograms of ricin, a dose the size of a pinhead, can kill.
To try to pin down the ricin’s origins,…
