Officials say a total of 50 flights were delayed Monday evening as a result of the investigation. Airport spokesman Greg Chin says nine flights were also diverted.
News agencies report some travelers missed their flights as a result of the delays.
Miami-Dade Police initially responded to the investigation before it was later turned over to the FBI.
FBI officials say a passenger who went through security around 5 p.m. had items in his carry-on bag that looked suspicious. Authorities say the passenger was questioned and his bag was searched, but the items in question were deemed safe.
Chin says checkpoints reopened around 8 p.m.