Insider Information

...on this.

From one in the know, a past source with demonstrated reliability, who has requested anonymity:

Never a doubt about negligent gun handling. Either the media or a police spokesperson came up with the "malfunction" or "trying to clear a round" story. Bottom line, that particular range has a no loaded weapons behind the firing line policy. The officers in question had been advised of this by other patrons (non-LEO regulars at that range) at which time they identified themselves as law enforcement and continued to load magazines and insert them into their firearms while at the counters along the wall behind the firing line. This placed them (and their loaded firearms) behind the non-LEOs at the firing line, that is why they mentioned the rules to the officers...non-LEO regulars had noticed sloppy gun handling just prior to the incident (particularly, fingers inside the trigger guard while not on target).