An “unprovoked” attack saw a man punched in the face as he waited for a burger at the Belladrum Tartan Heart Festival.
The 40-year-old was standing at a food van in the red camp area at around 10.30pm on Friday, July 29 when he was assaulted.
He was treated at the first-aid site, before then being transferred to Raigmore Hospital with a serious facial injury.
Detective Constable Ross Cooper, from Inverness CID, said: “This appears to have been an unprovoked attack and enquiries are ongoing to establish the full circumstances.
“The festival site was busy at the time and we are keen to speak to anyone who saw what happened or who has information that could help with our investigation.”
Police said anyone with information can contact 101, quoting reference CR/0034689/22, or make a call anonymously to Crimestoppers on 0800 555 111.