SPOKANE VALLEY -

The mysterious "boom" heard by multiple Spokane Valley residents Wednesday night has been identified as an improvised explosive device.

The Spokane County Sheriff's Office received 911 calls Wednesday night around 10:20 from residents report seeing a bright flash and a loud "boom" but investigators were not able to find any evidence of an explosion.

Two days later, evidence was recovered near Sprague and Robbie that will be submitted to forensics for examination. They'll be searching for fingerprints.

The IED had a fuse which was lit shortly before it was lifted into the air by a number of helium-filled balloons. There were not anti-personal components to the device, according to the Sheriff's Office, but it could have caused injuries or caused a wildfire.

The Sheriffs Office points out that there was no apparent connection between this device and the IED recently found along the route of the Martin Luther King parade in Spokane.

Information regarding the incident can be forwarded to investigators via Crime Check, 456-2233.