WASHINGTON – A government official said Friday that a scientist has been detained in Miami after screeners found a metal canister in his luggage that looked like a pipe bomb.

The official also said the FBI and Miami Dade police are interviewing the 70-year-old man. No explosives have been found. The official spoke on condition of anonymity to discuss the ongoing investigation.

Although law enforcement officials found no explosives, the suspicious item that looks like a pipe bomb is still being tested for contaminents, Homeland Security spokesman Nicholas Kimball said.

Four of Miami International Airport's six concourses along with an onsite hotel were evacuated Thursday evening. A bomb squad spent hours scouring the airport and passengers were evacuated from the complex Thursday night and airport roadways were closed down. Police and airport officials described the shutdown of the four concourses as a safety precaution.

The airport fully reopened just after 4 a.m.