A world-renowned scientist who sparked a bio-terrorism scare seven years ago was detained by police after a canister he was carrying sparking an airport shutdown and bomb squad search.
Officials shut down most of Miami International Airport overnight, woke nearby hotel guests and held Dr Thomas Butler until Friday morning, when he was released without charge, a senior law enforcement official said.
Tests on the canister found nothing dangerous, said the official. Homeland Security spokesman Nicholas Kimball said the item resembled a pipe bomb.
Butler's former lawyer said the incident appeared to be a "fantastic overreaction".
Butler, 70, quickly became the focus of a US government investigation in 2003 when he reported that 30 vials of plague samples had possibly been stolen from his Texas Tech University lab.
He was later acquitted of smuggling and illegally transporting the potentially deadly germ and of lying to agents about the missing vials. But jurors found him guilty of the mislabelling and unauthorised export of a FedEx package that contained plague samples he sent to Tanzania. He was also convicted of fraud and theft and sentenced to two years in prison for defrauding Texas Tech about illegally-negotiated contracts he had with pharmaceutical companies with which he also had clinical studies contracts.
The senior law enforcement official said on Friday night that a Transportation Security Administration inspector noticed an odd container at around 9pm on Thursday as Butler was going through customs at Miami. He had arrived on a flight from the Middle East, where he had been teaching at a Saudi Arabian university.
The inspector ran Butler's name through a database and discovered that he had been tried on the plague-related charges. Officials decided to evacuate the airport and detain Butler, who co-operated fully, the law enforcement official said. A Miami-Dade police bomb squad spent hours scouring the airport.
Butler was released after tests showed that he, the container and his other belongings did not contain any hazardous biological material or explosives, the official said.
The canister was used to transport dead bacteria samples and was a legitimate experiment, said another government official. Without naming Butler, the official said the scientist was a professor at Ross University, a medical school in Dominica, and on a teaching assignment in Saudi Arabia.