Actually the violence was the problem. Had this organized crime syndicate had the good sense to merely threaten violence and walk away with the phone they could have operated for years. But you show the public at large a video where a guy gets cold cocked, stripped to his underwear, a planter broken over his head, and run over by bicycles it doesn't play well.
Add to that the mundane fact that we all have phones and it was a real call to action. One of those rare circumstances where local news bothered the police brass.
Hopefully it's over and done but it can't be overstated that the money from the phones in no way sustained all 8 attackers let alone their families so the violence is actually the root cause. Random violence is scary.