Austin , Texas ( CNN ) -- A man accused of flying a small plane into an Austin building housing an Internal Revenue Service office last week was one of two people killed in the incident , Texas authorities confirmed Monday . The man who authorities say was the pilot , Andrew Joseph `` Joe '' Stack III of Austin , and Vernon Hunter of Cedar Park have been identified as the two people killed Thursday , according to the Travis County medical examiner 's office . Both men died from blunt force injuries , said Sarah Scott , chief administrative officer for the medical examiner . Authorities say that on Thursday , Stack flew a single-engine plane into a seven-story building that held offices for nearly 200 IRS workers . Two other people were hospitalized . Hunter and his wife , Valerie , worked at the IRS office in the building , his brother Harold L. Jackson told CNN affiliate WAAY . Hunter spent the past 15 years as a collections agent and previously served 22 years in the Army . Jackson said Hunter was the youngest of five brothers . Hunter was adopted as an infant and kept his birth name into adulthood . `` We called ourselves the Jackson Five , the other Jackson Five , '' Jackson said . Agents were looking into whether the seats of the plane were removed to accommodate a fuel drum in an effort to cause maximum damage , an official familiar with the investigation said Friday . The official , who could not speak on the record because of the ongoing investigation , said that the Piper Cherokee PA-28 had several seats removed and that a fuel drum was missing from the airport where authorities say Stack took off . The single-engine plane has a fuel tank capacity of 38 gallons and is equipped with four seats , according to the Web site risingup.com . Authorities say Stack also torched his $ 230,000 home in Austin on Thursday morning before embarking on his fatal flight . A 3,000-word message on a Web site registered to Stack railed against the government , particularly the IRS . Read the apparent suicide note ( PDF ) `` 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 , '' the online message says . `` 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 . '' Stack 's wife , Sheryl Stack , expressed her `` sincere sympathy to the victims and their families '' in a statement read by family friend Rayford Walker on Friday . Friends and former colleagues have said they had no inkling of the rage apparently building inside Stack . `` He hid that very well , '' said Billy Eli , in whose band Stack played bass until a few years ago . `` Obviously , he was in some serious distress and had some real despair . I never saw that . ''
Victim worked in IRS office in building where crash happened , WAAY says . Both men died from blunt force injuries , medical examiner 's office says . Authorities : Andrew Joseph Stack crash his single - engine aircraft into seven - story building . He set his home on fire before his death , authorities say .