Hertfordshire Constabulary has charged 55-year-old Ian McLoughlin with the murder of Graham Buck in Little Gaddesdenon Saturday, July 13. Mr. Buck had been stabbed to death after going to assist a neighbour who was being robbed.
Three other people were arrested in Tottenham, north London, at the same time as McLoughlin, police said.
The 54-year-old man from Tottenham, 45-year-old woman from Edmonton, north London, and 50-year-old man from Hackney were arrested on suspicion of assisting an offender.
All four are being questioned at Hatfield police station, Hertfordshire Police said.
The unlicensed events unfolded on Saturday night at Clapham Common and Tooting Bec Common.
A 37 year old man who was taken to hospital after getting into difficulty in a stretch of water near Maidenhead has died.
Jonty Bravery, who is mentally ill, has been jailed for 15 years after throwing a six year old boy from the Tate modern balcony.