Evacuated passengers at all terminals had to go through the security screening process all over again before boarding their flights.
A ground stop initiated for departing flights lasted about 20 minutes before it was lifted at 10 p.m.
However, bystanders reported seeing police detaining a man wearing a Zorro costume, who fell to the ground then crawled away from the building, and lay spread eagle, apparently in response to police orders.
One witness said she had seen the Zorro man greet a woman outside terminal 7, but police yelled at him and pulled a gun, so everyone tried to get away fast. Some people dropped their bags or even tried to climb up the luggage chutes to hide.