A 51-year-old man has head injuries after he was assaulted at a South West campground last night.
Police said the man suffered the wounds during an altercation at Glen Mervyn Dam, between Mumballup and Collie, about 7pm.
The man is being treated in hospital and his injuries are believed to be serious.
Detectives would like to speak to a man about the incident who is described as 20 to 30 years old and about 183cm tall with a solid build, fair skin, short light curly hair and sleeve tattoos.
He was driving a cream four-wheel-drive utility with no number plates.
Anyone who was in the area at the time or has information about the incident or the person and vehicle police are looking for is asked to contact Crime Stoppers on 1800 333 000.