Officers spoke as they appealed for three men and the occupants of a black Range Rover-type vehicle seen in the area to come forward.
Steven Donaldson’s body was discovered by two members of the public in the car park at Kinnordy Nature Reserve near Kirriemuir, Angus, at 5am on Thursday.
Police said the 27-year-old from Arbroath had been the victim of a “sustained and brutal attack” with a sharp, heavy weapon.
The senior investigating officer, Detective Superintendent James Smith of the major investigation team, is urging anyone with information to speak to officers.
He said: “I’d like to re-assure the public that every effort is being made to trace whoever is responsible for his brutal murder.
“I’d like to thank the public that have come forward so far, however I am convinced the answers to what has happened sit within the communities of Angus.
“Please do not think that the police have all the answers, we need information and people to come forward with that information, no matter how small or insignificant it may be.”