Joel Eldridge, whose 30th birthday was on Friday (March 8), travelled to Portugal in January 2018 to work but has not been heard from since July 2018.
His parents Jacki and Alan, from Bexhill, have made a video appealing for help from anyone who knew Joel in the UK or Portugal,
In it Jacki Eldridge says: “We know somebody knows something, please if you know anything, if you have heard any rumours about where Joel might be, if you have seen Joel, who was the last person to see him...please get in touch with Sussex Police and tell them what you know.”
Detectives in Britain and Portugal believe information from friends and associates of Joel, in Sussex as well as in Portugal, could help solve the mystery.
Joel went to Portugal in January 2018 to work on a house near Coimbra. He was living in Macieira near Serta when his family last heard from him in mid-July and by a UK-based firm which had an enquiry from him on July 26 about potential work in the UK.
His family said it is very unlike Joel not to be in touch as he had always kept in close contact with them, mainly via social media.
They said he has missed several family birthdays and failed to make any contact with his relatives throughout the Christmas and New Year period, none of which has ever happened before.
He is white, 5ft 10in, and of muscular build.
Joel’s disappearance was reported to Sussex Police in late August and police issued an appeal for information on August 31.
Detectives from the Surrey and Sussex Major Crime Team are working with the national Portuguese Judicial Police and have visited Portugal to meet their counterparts, police confirmed.
The Portuguese Judicial Police, which is leading the investigation with Sussex Police support, is treating the case as a potential suspicious death and it is being investigated by homicide officers.
Detective Chief Inspector Chris Friday, of the Surrey and Sussex Major Crime Team said: “Our enquiries, supporting those of the Portuguese investigators, give us cause to believe that Joel has come to harm at the hands of others while in Portugal.
“Anyone who may have heard from Joel since he went missing in July 2018, or who may have any other information about him or about anyone else who knew him, in the UK or Portugal, is asked to contact Sussex Police online or by calling 101, quoting Operation Lyra.
“You can also contact the independent charity Crimestoppers anonymously on 0800 555 111.
“In Portugal information can be given to the Polícia Judiciária in Coimbra on (+351) 239 863 000.”