The suspects had been under observation since October 2006, when the NSA had intercepted communications between them and IJU and alerted German authorities. At the end of 2006, Fritz Gelowicz was spotted suspiciously observing a US Army base in Hanau. The suspects had rented a vacation house in the remote town of Oberschledorn, where they amassed 700 kg (1,500 lbs) of hydrogen peroxide, and military-grade detonators from Syria.