A world-renowned Texas scientist specializing in infectious diseases who was once charged with smuggling dangerous samples of plague bacteria into the U.S. was questioned by authorities after a suspicious item found in his luggage caused a massive evacuation at Miami International Airport [on September 2]. Dr. Thomas C. Butler, 70, was questioned by agents with the FBI and Miami-Dade police [on September 3]. Initial tests on the item have come back negative. Butler was released from questioning and won't be charged in the incident. Sources told NBC Miami that Butler had been coming from Saudi Arabia when the suspicious item was spotted in his luggage as it went through customs. Butler had been on the faculty at Texas Tech since the late 80s until his arrest in 2003 on charges of smuggling and improperly transporting the plague samples, as well as theft, embezzlement and fraud. He was eventually found guilty of exporting the vials of plague and stealing research money. Butler spent nearly two years behind bars and lost his Texas Tech job, despite the protests of several in the scientific community who denounced his prosecution. His controversial story was even featured in a 60 Minutes" piece titled "The Case Against Dr. Butler." He's currently listed as a faculty member at Alfaisal University in Saudi Arabia.