The police have urged three people who came to the aid of a man assaulted in Edinburgh to come forward.
The incident happened at about 0100 BST on Saturday, 22 May, in Crewe Road North in the Granton area of the capital.
The 24-year-old victim had been walking with his girlfriend in Crewe Road North and had reached the railway when a gang attacked him.
He remains in a "serious condition" in the Western General Hospital.
Three males, aged 15, 15, and 17, have been arrested and charged in connection with the incident.
All three appeared at Edinburgh Sheriff Court on Monday 24 May, where they were released to appear at a later date.
Police are now appealing for a number of witnesses to the assault to come forward. In particular, officers want to trace three men who were travelling in what has been described as either a black 4X4 or taxi, who came to the aid of the victim after the assault.