However, the letter signed by Joseph Stack suggests Thursday's attack was an intentional act of domestic terrorism against the U.S. government.
In what would amount to a suicide note posted on the Internet, the man identified as pilot Joseph Stack urged the Internal Revenue Service to take his pound of flesh. On Thursday at 10 a.m., that is precisely what happened when Stack flew his own airplane into a Texas office complex.
There were 190 IRS employees in the building when the Cessna single-engine plane plowed into the side. Two bodies have been found. Thirteen others are injured. Stack is presumed to be one of the dead. Witnesses said it felt like a bomb, and looked like September 11th.
Despite the almost instant admonition from federal and local officials that this was not terrorism, authorities say it was a deliberate act that amounted to a suicide attack.
The pilot of the aircraft has been identified as 53-year-old Joe Stack, a software engineer from had moved from California to Austin. Stack had it out for the Internal Revenue Service, what he saw as illegal taxation and the decline of an America as he wanted it. Before crashing his plane into the building, police say stack set his own home on fire not far away. A short time after the incident, the ABC7 I-Team found a Web site registered to Stack at his home address. The 6-page manifesto, said to be written by Stack, rails against the government and the IRS. The diatribe begins with a question that seems to refer to the suicide attack, "Why did this have to happen?"
"I know I'm hardly the first one to decide I have had all I can stand," writes Stack in the diatribe left on a Web site http://embeddedart.com/ that is registered to Stack.
When the crash occurred, a pair of F-16 fighter jets were put in the air from Houston but were returned after no foreign terrorist connection was determined. A missing government worker has not been identified, but is a collection agent from the IRS. Austin Fire Department Battalion Chief Palmer Buck said late Thursday that authorities "have now accounted for everybody," but declined to discuss the identities of those found.
The Associated Press contributed to this report.