Internal Revenue Service | ORGANIZATION

People stand around outside the Internal Revenue Service building in Ogden, Utah after hazardous materials and fire crew members arrived on Monday, March 1, 2010. Emergency workers were called to the building after a suspicious substance was found.

Paramedics in hazardous materials protective clothing wrap up a person on a stretcher outside the Internal Revenue Service building in Ogden, Utah on Monday, March 1, 2010. Hazardous materials crews were called to the building after a suspicious substance was found.

Members of the Patriot Guard line the road with American flags as they await the arrival of friends and family of Internal Revenue Service employee Vernon Hunter, 68, for his memorial service at St. James Missionary Baptist Church in Austin, Texas, on Friday, Feb. 26, 2010. Hunter was killed when Andrew Joseph Stack III intentionally crashed his plane into the office building which housed offices for the IRS where Vernon Hunter worked on Feb. 18, 2010.

In this undated photo provided by Texas Department of Public Safety, Joseph Stack is shown. Stack, authorities said, flew his small air plane into an office building in North Central Austin, where several employees of the Internal Revenue Service worked. Stack and one IRS employee, Vernon Hunter, 68, a Vietnam veteran and father of six who worked for the IRS nearly 30 years, were killed in the attack.

People stand on an embankment across U.S. 183 from a building that was destroyed by a small airplane as they take pictures of the aftermath in Austin, Texas, Saturday Feb. 20, 2010. Authorities said that shortly after taking off from Georgetown Municipal Airport, Thursday, Joseph Stack flew his small airplane into the building where several Internal Revenue Service employees worked.