Officers are appealing for information after a 40-year-old man was seriously assaulted in Dumbarton.
The incident happened around 9.15am on Sunday, September 4, within a property on Murroch Avenue.
The man was taken to Queen Elizabeth University Hospital for treatment.
Three men, aged 40, 18 and 17, were arrested in connection with the incident and released pending further enquiries.
Detective Constable Thomas O’Donnell, of Clydebank CID, said: “Our enquiries into this incident are ongoing and I would urge anyone with information to get in touch.
“We would be keen to speak to anyone who may have seen or heard any disturbance in the area, or any local residents who have any information that could assist our investigation to contact us.
“Anyone with information should call police via 101, quoting reference 1314 of 4 September, or call Crimestoppers anonymously on 0800 555 111.”