Paul Kevin Curtis, the 45-year-old Mississippi man arrested Wednesday in connection with the possibly ricin-tainted envelopes sent to President Obama and at least one senator, has taken to Facebook in recent years to claim he knows of an organ-harvesting scheme. He's also an entertainer.

Just a day after a pair of explosions brought terror to the Boston Marathon, letters containing the poison ricin started turning up in the mail of senators and President Obama. So far the suspicious packets have been intercepted in the security procedures adopted after the post-Sept. 11 anthrax attacks.

Ricin is a naturally occurring toxin found in castor beans. You can get sick by eating beans. But purified ricin can be made pretty easily and used for no-good.

Envelopes sent to a senator and President Obama contained a substance that initially tested positive for ricin.