I live in the area and know a couple of the people involved.
The name on social media is not the person who committed the crime. It's either a fake account or a bot. Either way, it's done its job and stoked up trouble. The usual names on social media around here have stirred the pot, added their own take, and the end result was last night's stupidity. My friend is related to one of the people involved and travelled up to be with them and go to the vigil and see his relative who was in the very thick of it. To say he is fuming about what played out afterwards is an understatement. It's not what his family wants or I should think anyone else's involved.
The lad that is credited with being one of those who intervened is a personal trainer at the gym as well as a window cleaner, so he was in a prime position with both youth and strength on his side to do something incredibly positive in what is otherwise a wholly negative situation. A brave individual indeed. I should think more will come out about people doing very brave acts over the next few days.
As of the individual who is in custody? Well the less speculated about him the better. His origins have been played up/assumed by the trouble makers and tapped in to an unpleasant undercurrent that social media carries.
All in all, a right 5H1t show of a start to the week.