Detectives are appealing for information after a man was found with a head injury in Weymouth.
Police was called by the ambulance service at 9.54pm on Saturday 19 January to reports that a man aged in his 20s had been found unconscious with a head injury on Beverley Road in Weymouth.
He was taken to Southampton hospital where he remains in a critical condition.
A cordon was put in place to allow officers to examine the scene.
Detective Sergeant Tom Hall, of Weymouth CID, said: "We have launched an investigation to establish exactly how the man came to sustain the injury and whether there was any third party involvement.
"I am appealing to anyone who witnessed anything suspicious in the area around the relevant time, or saw what happened to the man, to please come forward.