Devon police have released CCTV images of Alan Jeal the night before his body was found washed up naked on Perranporth beach, with a rolled-up sock and headphones in his mouth.
His body, which sustained injuries to the chest, head and hand, was discovered on 25 February 2014 by a dog walker.
The 64-year-old, who was discovered wearing only socks and a single walking shoe, suffered significant internal injuries, a flesh wound to his scalp and a bleeding hand.
But while there were also some signs of possible drowning, a cause of death has not yet been confirmed.
It was originally thought Jeal caught a bus from Truro to Perranporth the night before he was found, but the latest CCTV shows him in Newquay before taking a bus to the resort town.
As well as his clothing, several of Jeal's possessions are still missing including a Barclays Bank card, a Nokia 1110i mobile phone and an iPod shuffle.
DCI Dave Thorne said: "Three months on and there are still some gaps in the information we have about Alan and his last movements.
"We are still treating his death as suspicious due to the extent of his injuries and the fact that he was found naked, with a sock and headphones in his mouth.
"There are a number of people we are keen to trace, including three people seen with him at the bus stop in Truro who have not come forward yet.
"We believe he may have had a friend in Plymouth and another in Redruth, and would like to speak to them as they may be able to provide crucial information and fill in some of the gaps.
"During the investigation we have discovered that Alan was into online gaming and detectives would also like to hear from anyone who interacted with him online.
"There are lots of theories about how he may have died but we don't know exactly what happened to him and we want to provide Alan's family with some answers."