The FBI is investigating what may have caused a dozen ducks to die in a large reflecting pool in front of the U.S. Capitol.

A swath of territory in front of the Capitol was closed late Friday after the findings.

Tests were being run and police were keeping people and vehicles away from the West front of the Capitol.

FOX News has learned there were reports of a strange odor in the air around the same time the dead fowl were discovered around 10:30 ET.

Nearby sidewalks had been undergoing improvements.