Backpack Explosion at Kootenai Fairgrounds, ATF and Bomb Squad Respond; Man Arrested

A backpack exploded or caught fire inside an event building at the Kootenai County Fairgrounds during a gold‑mining vendor event, and a 21‑year‑old man was detained and arrested at the scene, deputies said. Kootenai County Sheriff’s Office deputies responded after dispatch received a report around 1:15 p.m. on March 8, 2026, and officers from the Coeur d’Alene Police Department helped detain the suspect.

Investigators allege the incident began when, following a dispute the day before, the son of one vendor approached another vendor and threw a backpack under the other vendor’s table. KXLY reported that the backpack “caught fire and was quickly picked up and thrown outside,” where it continued to burn until first responders arrived. Spokane County Sheriff’s Office Bomb Squad personnel and Kootenai County Fire and Rescue rendered the backpack safe on site.

Authorities identified the detained man as John P. Marsh, 21, of Midpines, California. Marsh was arrested on suspicion of arson, aggravated assault, and obstructing a police or peace officer, with sources using slightly different wording for the obstructing charge. Investigators say the probe is ongoing and that additional charges are possible.

Scene examination turned up further hazards: investigators later found additional accelerants inside the backpack that did not ignite. IdahoNews noted that the Bureau of Alcohol, Tobacco, Firearms and Explosives has been contacted and will assist with the investigation, and that the Coeur d’Alene Police Department is assisting because the vendors were staying at a hotel in Coeur d’Alene.

No injuries were reported, and organizers allowed the gold‑mining vendor event to continue after the scene was secured. Deputies and Coeur d’Alene officers remained on scene while bomb squad and fire personnel completed hazardous‑materials mitigation and safety checks before reopening the affected area.

The incident raises immediate public safety and event‑security questions for the Kootenai County Fairgrounds and for organizers of vendor shows that draw out‑of‑area attendees. Local law enforcement provided the timeline, the arrest, and the evidence of unignited accelerants, but described the initial report both as a backpack that “exploded” and as one that “caught fire,” language that officials have not reconciled publicly. Kootenai County detectives have not released a motive and are continuing evidence collection.

Investigators urge anyone with video or eyewitness information from inside the event building around 1:15 p.m. on March 8 to contact the Kootenai County Sheriff’s Office. The case, now involving KCSO, Coeur d’Alene PD, Spokane County Bomb Squad, Kootenai County Fire and Rescue, and ATF assistance, remains under investigation and could lead to formal charges beyond the initial arrest allegations.