They found a number of devices as well as grenades, which can only be obtained through the military. The devices were removed from the site and rendered safe, according to Dorschner.
As children rolled by in wagons, Tom Cole told CNN affiliate KUSA about how he had heard him doing metalwork into the night.
"There were many times this goes on until 9 o'clock at night, and you hear a grinder," Cole said.
Another neighbor, Michelle Chalupa, told CNN affiliate KMGH her children had "talked to (Sandberg) before (and) he seemed like a very nice guy."
"It's so scary," she said. "... I'm thankful that whatever operation found it before somebody was hurt."