Joseph Andrew Stack

A small private plane that reportedly belonged to Joseph Andrew Stack crashed into the Echelon office building, very close to FBI and IRS offices in Austin, Texas, on Thursday morning.

Authorities now say that Stack committed suicide in the plane crash, according to CNN.

In addition, A message on a website owned by Stack reportedly includes a suicide note written by Stack. In the note, Stack apparently writes of his hatred for the IRS and the U.S. government.

At this time, authorities believe that the plane crash was a “criminal act” linked to an act of arson that happened 30 minutes before the crash, according to News 8 Austin.

Joseph Andrew Stack

The plane reportedly crashed into a building next to the Professional Education Center of St. Edward’s University, a private Catholic university, while classes were in session. Officials have not released information about casualties yet, but the university’s website currently states that “All employees and students that were in the building have been accounted for” and that the building has been evacuated. While the Professional Education classes have been cancelled for the day, the rest of St. Edward’s classes will not be changed. The university currently enrolls over 5,000 students, including undergraduate and graduate students.

The circumstances of the damage to the building next to the Professional Education Center are still unclear.

Update: According to sources for CNN, the plane that crashed was Piper Cherokee PA-28.