A good samaritan was left with a broken jaw when he was attacked shortly after he split up a fight in Brighton.
Two boys and a girl set upon the 23-year-old man at The Level during one of the final events of the Brighton Festival.
The victim had broken up a fight between two groups of teenagers some time between 11pm on Friday 13 May and just after midnight.
Shortly afterwards two boys and a girl returned to the man and beta him up, breaking his jaw.
Detective Constable Caroline Biggs said: “This is a serious assault on an innocent member of the public who tried to help dissolve an argument between teenagers.
“He has been left very shaken by the incident.
“The assault occurred during a fire event at The Level as part of the Brighton Festival.
“I am appealing to anyone who attended this event and may have witnessed the fight and the subsequent assault to please contact police.”
Both teenage boys were described as being white and aged 17 to 20 years old.
The first boy was described as being 5ft 10in tall, of stocky build and with short mousy brown hair.
He was wearing a grey tracksuit with white stitched letters across the zip-up hoodie.
The second boy was described as being 6ft tall, of lean build and with short cropped mousy hair.
The girl was described as being dark skinned, Afro-Caribbean, of petite build, under 5ft tall and wearing a denim jacket.
Neighbourhood officers have been helping detectives and have been viewing CCTV footage.
Anyone with information is asked to contact Sussex Police on 0845 6070999.