[zeugma]

There are conflicting accounts of what happened next. One that hasn’t been reported before describes a man in a yellow full face helmet firing a stainless steel or chrome revolver. The man has never been identified although CNN does possess a photo of a yellow full face helmet sitting in the grass.

I'd be willing to bet that this is a fed.

[XenaLee]

Probably an undercover embedded officer that, after alerting the local authorities to the meet-up, made damned sure that he started the shooting fiasco so the cops could arrest everyone. This is the stuff that movies are made of.