Although the fireballs are regularly seen on the river during the Phayanak Festival, a 2002 iTV documentary showed Lao soldiers firing tracer rounds into the air across the river from the festival. Skeptic Brian Dunning suggests that it would be impossible for anyone across the half-mile river to hear a gunshot because it would take 2.5 seconds for the sound to travel to the spectators, and by then the crowd watching would have already noticed the light and started cheering, drowning out any sound to reach them. Thai biologist Jessada Denduangboripant analysed footage of a Naga fireball event and concluded that the effect was caused by the firing of flare guns from the other side of the river. A 2021 official investigation by Lao authorities during a COVID-19 lockdown and curfew, concluded "In response to the news in foreign media, I would like to state that it is extremely unlikely that anyone could have fired weapons or flare ammunition without our knowledge on that night. We ensured a heavy police presence through the night and did not encounter any incidents".