WBRZ - Baton Rouge

UPDATE: U.S. law enforcement officials say they are investigating whether the crash of a small plane into a building in Austin, Texas, may have been an intentional act by the pilot.

The officials said authorities are trying to determine if the pilot intentionally targeted nearby office space of the Internal Revenue Service. There are reports the pilot may have been disgruntled with the IRS.

As a precaution, the Colorado-based North American Aerospace Defense Command launched two F-16 aircraft from Houston's Ellington Field, and is conducting an air patrol over the crash area.

Fire department officials say one person is unaccounted for following the crash. Two others have been taken to a hospital. Their conditions were not immediately known.