Two men have been arrested on suspicion of the murder of a 22-year-old man.
One suspect, a 37-year-old man, is under police guard in hospital where he is recovering from multiple injuries "sustained during the same incident".
Police said the death was believed to be an isolated incident between a group of men known to each other.
The victim died on Saturday after suffering a "significant" head injury at Kelly Bray, near Callington, in Cornwall on Thursday.
Police arrested a 37-year-old man and a 29-year-old man, both from Gunnislake, on suspicion of murder.
A 38-year-old man and a 26-year-old man, both from Callington, have also been arrested on suspicion of the attempted murder of a 37-year-old man during the same incident.
The suspects have been released on police bail.
Devon and Cornwall Police said it was not looking for anyone else in connection with the incident.
Det Insp Rob Back said: "This has been a very fast moving enquiry and I would like to thank the communities within east Cornwall for all the support they have provided, particularly those who have been socially distancing or self-isolating."
Anyone with information is asked to contact police on 101.