suspicious package

(via Wikimedia commons/SSGT CHAD R. GANN, USAF)

The source of an irritant that sent three mail center workers at a southwestern Illinois air base to the hospital may forever be a mystery.

A Scott Air Force Base spokesman says authorities were unable to pinpoint what caused Wednesday's illnesses and a brief evacuation of that portion of the installation. The spokesman says the investigation is now closed.

(via Wikimedia commons/SSGT CHAD R. GANN, USAF)

Updated at 3:11 pm: According to the St. Louis Post-Dispatch, the three people taken to the hospital were an airman and two civilian base employees. Col. Michael Hornitschek told the Post that the package had been isolated and the FBI had been called into investigate as part of standard procedure.