Austin , Texas ( CNN ) -- Lisa Alexander woke up early on February 18 , the same way she does every morning . `` My alarm usually goes off at 4:30 , 4:45 , '' she said . `` I lay in the bed and kind of plan out my day . '' She had no idea that her life was about to be targeted by a man with a vendetta against the government . She got up , woke up her son and headed to work at the IRS offices in Austin . `` The first thing I do is get in , organize my desk and wipe it down ... fire up my computer and tell everybody good morning , '' Alexander said . `` Before I know it , the building kind of went to the left and came back ... `` I thought it was an earthquake . '' It was n't . Just a few minutes before 10 a.m. , a single-engine Piper Cherokee PA-28 crashed into the multistory building where Alexander worked . `` It was like an explosion , '' she said . `` The windows started breaking out and the tiles started falling from the ceiling , and then it was dark . '' Alexander said she went to check on her co-workers , and they headed for the nearest door . `` As we open the door , this 'poof ' sound comes in as if it were a flame or something behind it , '' she said . `` So we immediately shut the door and we smelled that smell , it was probably jet fuel . '' They closed the door and stood there , trying to figure out how to escape . `` The first thing that crossed my mind is I 'm not going to see my son anymore , '' Alexander said . A few blocks away , Robin DeHaven was driving his truck on his way to install windows when he spotted something strange in the sky . `` I looked on the horizon and I just saw a little dot and ... I 'm staring at it like , 'What is this ? It does n't look like a bird or anything . ' `` DeHaven said . `` And I realized it was a plane . '' Realizing there was no airport around for miles , he figured the pilot must be having problems . `` When I saw it disappear , within seconds I saw a big plume of black smoke , '' he said . `` I exited the highway , and I saw that all this smoke was coming from this building . All I saw was all the shattered glass and all the smoke coming out , and I thought , 'Oh jeez , he hit a building . ' `` Authorities say they believe the pilot , Joe Stack , had ripped seats out of the small plane and put in a drum of fuel to cause maximum damage . Stack allegedly set fire to his $ 230,000 home in Austin before embarking on his fatal flight . Read Stack 's apparent suicide note ( PDF ) Investigators believe Stack targeted the building because it housed IRS offices . A 3,000-word message on a Web site registered to Stack railed against the government , particularly the IRS . Alexander did n't have time to think about what had happened , or why someone had crashed a plane into her office building . `` We were all screaming for help , '' she said . `` By that time , the smoke was getting real bad . I kind of crouched down on the floor trying to get some air from under there . `` And [ I was thinking ] I 'm going to have to jump because it 's getting worse in here . '' The next thing she knew , she saw what she thought was `` an angel from heaven . '' Alexander and the others survived . But the attack killed one of their co-workers , longtime IRS employee Vernon Hunter . He was 68 . Alexander said she had a lot of memories of Hunter , whom she worked with before her job at the IRS . `` He 'd do anything for you , '' she said . She questioned why he , of all people , had to die . But she said the tragedy actually made her faith in God stronger . `` I 've been raised all my life to go to church and believe in God , and it 's like , you know , maybe it 's time for me to start believing , '' Alexander said . `` And that 's when it came to light that this was my test . `` I 've really lived a good life . I 've never come so close to death . I 've had family members die , and it was a little different . But when it faces you , it 's a different feeling . '' CNN 's Brian Rokus and Tricia Escobedo contributed to this report .
Lisa Alexander is an IRS revenue officer in Austin , Texas . She has been a tax professional for over 20 years and she can be reached at [ lisaalexander@irs.gov ] Authorities say Joe Stack , angry at the government , flew his plane into the multistory building .