The Boulder County Bomb Squad detonated an explosive device that prompted authorities to evacuate an entire shopping center the day before.

The controlled detonation occurred at around 1:30 a.m. Wednesday. The device was discovered outside of the Nederland Marshal’s Office at around 8 a.m. Tuesday. This led to the evacuation of the Caribou Ridge Shopping Plaza, which has since reopened.

Officials said moving the device would compromise the safety of the public, which is what prompted the detonation.

Town Marshall Paul Carril said 1,200 Nederland residents received notification calls that the detonation was going to occur. It was supposed to sound similar to a firework boom.

It’s unclear exactly what the explosive device was, or who left it in the area.

County and federal agencies are helping Nederland Police with the investigation.