AUSTIN — A software engineer furious with the Internal Revenue Service launched a suicide attack on the agency Thursday, crashing his small plane into an office building containing nearly 200 IRS employees, sending workers running for their lives.

Emergency crews recovered two bodies from the wreckage. The pilot was presumed dead, and one worker in the building had been missing.

Austin Fire Department Battalion Chief Palmer Buck declined to discuss the identities but said authorities had “accounted for everybody.”

The FBI tentatively identified the pilot as A. Joseph Stack III, 53.

Law enforcement officials said that before taking off, Stack apparently set fire to his house and posted a long anti-government note on the Internet.

In it, the author cited run-ins he had with the IRS and ranted about the tax agency, government bailouts and corporate America’s “thugs and plunderers.”

“I have had all I can stand,” he wrote, adding: “I choose not to keep looking over my shoulder at ‘big brother’ while he strips my carcass.”

The pilot took off in a single- engine Piper PA-28 from an airport in Georgetown, about 30 miles from Austin.

He flew over Austin before plowing into the side of the seven-story, black-glass building just before 10 a.m.

Flames shot from the building, windows exploded, a huge pillar of black smoke rose over the city and terrified workers rushed to get out.

“It felt like a bomb blew off,” said Peggy Walker, an IRS revenue officer who was sitting at her desk. “The ceiling caved in and windows blew in. We got up and ran.”

At least 13 people were injured, with two reported in critical condition. About 190 IRS employees work in the building.

The building, in a heavily congested section of Austin, was still smoldering six hours later, with the worst of the damage on the second and third floors.

The entire outside of the second floor was gone on the side of the building where the plane hit.

It was not clear if any tax records were destroyed.

Andrew Jacobson, an IRS revenue officer who was on the second floor when the plane hit, said about six people couldn’t use the stairwell because of smoke and debris.

He found a metal bar to break a window so the group could crawl out onto a concrete ledge, where they were rescued by firefighters. His bloody hands were bandaged.

Stack’s ‘rant’

In the long, rambling, self-described “rant” that Stack apparently posted on the Internet, he began: “If you’re reading this, you’re no doubt asking yourself, ‘Why did this have to happen?’ ”

He recounted his financial reverses, his difficulty finding work in Austin and at least two clashes with the IRS, one of them after he filed no return because, he said, he had no income.

The other came after he failed to report his wife Sheryl’s income.

He said he slowly came to the conclusion that “violence not only is the answer, it is the only answer.”

“I saw it written once that the definition of insanity is repeating the same process over and over and expecting the outcome to suddenly be different. I am finally ready to stop this insanity. Well, Mr. Big Brother IRS man, let’s try something different; take my pound of flesh and sleep well,” he wrote.

The blaze at Stack’s home, a red-brick house on a tree-lined street in a middle-class neighborhood six miles from the crash site, caved in the roof and blew out the windows.

Elbert Hutchins, who lives one house away, said the house caught fire about 9:15 a.m.

He said a woman and her daughter drove up to the house before firefighters arrived.

“They both were very, very distraught,” Hutchins said. “ ‘That’s our house!’ they cried. ‘That’s our house!’ ”

Red Cross spokeswoman Marty McKellips said the agency was treating two people who live in the house and the family had no comment Thursday.

McKellips said the family would “give information and answer questions” today.

Thursday was not the first time a tax protester went after an Austin IRS building.

In 1995, Charles Ray Polk plotted to bomb the IRS Austin Service Center. He was released from prison in October of last year.

The tax protest movement has a long history in the U.S. and was a strong component of anti-government sentiments that surged during the 1990s.

Anti-tax protesters typically believe that they do not have to pay income taxes. Some have been convicted in recent years for targeting IRS officials for harassment and even murder.