A man has been critically hurt and another man broke his nose in a serious assault in Worcestershire.
A taxi driver in Unicorn Hill, Redditch, called police after he spotted the attack at about 0230 BST on Friday.
Two men were taken to hospital and two other men in their late teens were arrested on suspicion of wounding and assault.
Police have urged the taxi driver who reported the assault to get in touch.
Anyone with information is asked to contact West Mercia Police or call Crimestoppers anonymously.