This happened in my town last year and is now at trial. Much the same as the Edlington boys but this time with adults, male and female alike (3 women 24, 30 & 41, 2 men 20 & 27) and lasting 3 days.
The victim, who was 22, ended up stabbing himself in the chest five times in an attempt to kill himself to escape the torture.
A 13 year old boy received a formal reprimand for taking part in the attacks.
I actually lived in a block of flats (not the one where the attack took place) at the same time as the 41 y/o woman lived there. Horrendeous when it's happening somewhere in the world, terrifying when it's on your door step.