Plane makes emergency landing in Miami

A threatening note forced a Boston-bound airplane to return to a Miami airport about 40 minutes after takeoff, but nothing suspicious was found.

Airport spokesman Greg Chin says a flight attendant found a note in one of the plane's bathrooms Thursday night that said explosives might be on board. American Airlines Flight 1640 had departed Miami International Airport around 9:30 p.m.

FBI spokesman Ricardo Enriquez says the word "bomb" was in the note.

The plane was searched and bags were re-screened after 168 passengers and six crew members safely disembarked. Transportation Security Administration spokeswoman Suzanne Trevino says nothing turned up in the search.

The passengers stayed overnight in Miami and left Friday morning for Boston.

The threat remains under investigation.