Now we know why Miami's airport evacuated last night: Something suspicious was found in the suitcase of a man previously jailed for smuggling the plague. Meet Dr. Thomas Butler, a white guy from Texas who works in Saudi Arabia.

Butler—who was making pit stop in Miami on his way from Saudi Arabia to Texas—is currently being questioned after authorities thought a "suspicious canister" in his suitcase was a pipe bomb. The canister has since tested negative for explosives, but is still being examined.

But Butler has an unusual past. Once a renowned scientist, he worked at Texas Tech until 2003 when he was convicted of stealing research money and exporting 30 vials of the bubonic plague. At the time of his arrest, Butler claimed that he'd been working on a plague antidote that would save the world in the event of bio-terrorist attack. But he ultimately served two years in prison, although his case was pretty controversial: 60 Minutes, for instance, did a segment portraying Butler as a respectable scientist and victim of post-9/11 hysteria.

After his conviction, Butler lost his job and decamped to Saudi Arabia's Alfaisal University. So it's no surprise that his bags get pretty thorough searches at the airport these days.

Butler, who is still in Miami, is "cooperative," according to investigators, although they have not announced whether they currently believe him to be on the side of good or evil. [NBC Miami, NYDN]