A man suffered serious injuries when he was assaulted and stabbed following a crash in Tunbridge Wells.
He was taken to hospital following the incident on Monday evening in Forest Road.
Kent Police said the man was assaulted by several people, with his injuries "caused by a bladed instrument". His injuries were not thought to be life-threatening.
His attackers left the scene and there have been no arrests.
Anyone with information is urged to contact police.
Emma Round was one of the first people on the scene following the collision at about 18:15 BST.
"It was really chilling... normally people are pulling together, and the people who are in the accident are obviously still on the scene, but this was much more sinister."
Local resident Lesley Bulmer added that she had seen "about eight boys all piled on top of each other".
"Seconds later they all dispersed, but the guy who was obviously on the bottom of the pile stood up, [and] gripped his left side.
"I immediately thought he's been stabbed," she said.