The body of Stewart Barrett, 34, from Kirkintilloch, East Dunbartonshire, was found close to the Carron Valley Reservoir near Fintry in Stirlingshire on Sunday.
Detectives are now trying to piece together his final movements and are appealing for anyone with information to come forward.
Central Scotland Police are leading the murder probe but are liaising with colleagues from Strathclyde Police.
Mr Barrett, a father of three, was last seen at 10.30pm on Saturday in Meiklehill Road, Kirkintilloch. His body was found at 11am on Sunday half a mile along a forest track at the north end of Carron Valley reservoir.
A post-mortem examination confirmed he died of injuries sustained during a violent assault.
DCI Willie Cravens, from Central Scotland Police, said: "We are keen to hear from anybody who may have seen him throughout Saturday, either on his own or with other people. He was wearing blue tracksuit bottoms, white trainers and a dark-coloured top."
Police are also keen to hear from anyone who was at the north end of the reservoir between 10.30pm on Saturday and noon on Sunday.
Anyone with information can contact Central Scotland Police on 01786 456000 or Crimestoppers on 0800 555111.