Austin, Texas - "If you're reading this, you're no doubt asking yourself, 'Why did this have to happen?' The simple truth is that it is complicated and has been coming for a long time."
So began a lengthy, rambling anti-government Web message believed posted by a Texas man suspected of crashing his small plane into an office building housing IRS employees.
The man, identified by federal law enforcement officials as Joseph Stack, 53, was a software engineer who had a long-running grudge with the Internal Revenue Service, whom he referred to in the screed as "thugs and plunderers."
The Web message was dated Thursday and signed "Joe Stack (1956-2010)."
Hours after posting it, Stack set fire to his home, drove to a municipal airport, got into his single-engine Piper Cherokee and deliberately crashed it into a multistory office building, authorities said.
Stack was presumed to have died in the crash, federal law enforcement officials said.
Crews found a body inside the building Thursday evening but police decliend to say if it was the pilot.
At least two people were seriously injured and a third person — a federal employee who worked in the building — was unaccounted for, fire officials said.
The crash caused a raging fire that sent black smoke billowing from the seven-story Echelon Building. The fire was extinguished hours later.
At an afternoon news conference, Austin police Chief Art Acevedo said the crash "appears to be an intentional act."
"It would appear to be by a sole individual, and it appears this individual was targeting federal offices inside that building," Acevedo said.
Rep. Lloyd Doggett, D-Texas, said in a statement that the crash was "a cowardly act of domestic terrorism." The police chief, however, said he preferred to describe it as "a criminal act by a lone individual."
The FBI was taking over the investigation.
About 190 IRS employees work in the building, and IRS spokesman Richard C. Sanford the agency was trying to account for all of its workers.
Violence 'the only answer'The pilot, listed in FAA and property records as Andrew Joseph Stack III of Austin and identified by law enforcement sources as Joseph Stack, apparently had a long-running dispute with the IRS.
