The peaceful protester shot in Salt Lake City yesterday has died.

[Igel]

3. Sounds like "protest-organizer-appointed militia."

Somebody gets out of hand, the organizers have enforcers to keep them in line. Whether "false flag" (as all such cases are) or the Antifa/Black Bloc folk who are clearly allies to the cause but have chosen to permit themselves different methods than the majority.

Conversely, if somebody approaches with evil intent, they're not just enforcers but also protestors.

"Private security" but plausibly of the unpaid type.

Could be wrong--perhaps they were paid. But the description should include that bit if true; excluded, one assumes by conversational implicature that it's not.