Four people including a 16-year-old boy have been arrested on suspicion of murder after a man was found collapsed in the street in Cornwall.

Colin Palmer, 57, was found unconscious in Biscovey, Par, near St Austell, in the early hours of Saturday morning, according to local reports.

He was taken to Royal Cornwall Hospital in Truro, where he later died, Devon and Cornwall Police said.

Three men, aged 21, 19, and 18, were arrested along with the 16-year-old at a nearby property, police said.

All four suspects live locally, police said. They remain in custody at Launceston and Newquay police stations.

The victim was found just after 2am at his home near the Eden Project.

The area, around St Marys Road and Robbins Close, has been cordoned off as forensic officers collected evidence.

A police spokesman said: "Following police inquiries, at 4.05am three local men aged 21, 19 and 18 and a local youth aged 16 were arrested at a property in the area on suspicion of murder.

"They remain in custody at Launceston and Newquay custody centres.

"Police are appealing for witnesses who were in the vicinity of St Marys Road and Robbins Close between midnight and 2am or anyone who has any information regarding this incident to contact them."

Ch Insp Mike Ward of Devon and Cornwall Police said the victim's next of kin had been informed.

A post-mortem examination will be carried out.