A social media account has been set up in the name of a man feared murdered four years ago, police have said.
Ricardas Puisys, 35, of Wisbech, Cambridgeshire, was last seen at work 20 miles away in Chatteris in September 2015.
A man arrested as part of a murder probe was released without charge.
Officers said photos of someone who appears to be Mr Puisys have appeared on a Facebook account in his name, but they have yet to confirm he is alive.
Friends became concerned about the Lithuanian national, who was last seen at Nightlayer Leek Company on 26 September 2015, but a police appeal failed to trace him.
Det Ch Insp Adam Gallop, from the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, said "early on in the investigation we had information that Ricardas had come to some harm" but there was insufficient evidence to charge anyone.
"For the past four years Ricardas' disappearance has been a complete mystery.
"To this day we have not found his body, nor have we found any evidence telling us he is alive. That was until last summer."
The Facebook account has been traced to the Wisbech area, and police are appealing for people in the town's Lithuanian community to contact them.
Det Ch Insp Gallop said: "Whether Ricardas is alive or not, someone knows what has happened to him.
"Please do the right thing and come forward."