Word on the street is she has ex-Blackwater running security for her.
Here's a DailyKOS description of what happened:
The focusing on Bernie has made BLM look weak - going after Sanders because he's tried to keep his campaign as open and as accessible as possible, while not a quip at other candidates' events - and the words being spoken at the Sanders rally soars into hyperbole (coming from me, I know, a hoot, but still) that makes it impossible to have an honest discourse. It's put the candidate who would do the best for BLM's goals into a lose-lose situation. Either get extra security and cut them off, looking like a racist pseudo-progressive, or keep letting them dominate and shut down events before they can even start, not even letting him speak and talking down to him like this is getting ridiculous. Scanning Twitter there were progressives of all races expressing frustration about this, and now the meme going around is they were bought out by Hillary/Soros.
At the end of the day shit like this is just going to get Hillary elected, or worse yet, get whoever winds up the Republican nominee elected - which would only make things even worse for black Americans. Sanders is the best thing we've got going and
Hillary has one of the most racist records a Democratic candidate in recent history has under her belt. It's foolish to think she'd do anything BLM demands while taking kickbacks from the prison-industrial complex.