A man was left bruised and battered after he was attacked in Dunstable last week.
The man was walking on Whipsnade Road by the Dunstable Downs between 4.30am and 5.30am on Friday, June 12 when he was set upon.
He was taken to hospital where he remains in a serious but stable condition.
Officers are appealing for witnesses to come forward. In particular, they want to speak to anyone who saw a group of four men walking from Dunstable town centre to the Dunstable Downs at around this time.
Anyone with information is asked to contact DC Emma Morgan on 101, text 07786 200 011, or call Crimestoppers, anonymously, on 0800 555 111.