A murder investigation has been launched into the disappearance of a former military bomb disposal expert.
Detectives from the Surrey and Sussex Major Crime Team are now investigating after Mark Manning, 54, of Brighton Road, Lancing, was reported missing on 22 April.
Mr Manning, who was a former military bomb disposal expert, is well travelled and worked for the Mines Advisory Group (MAG), a charity that removes landmines and other dangers in some of the world's poorest countries.
His family last heard from him on 19 April. They say his disappearance is completely out of character and he has never done this before.
Detective Chief Inspector Mike Ashcroft, who is leading the investigation, said: "Although we can't categorically prove that Mark is dead at this time, we are treating this as seriously as we can.
"His sudden disappearance is completely out of character. He is close to his family but they have not heard from him at all.
"He hasn't used his mobile phone, or carried out any financial transactions, hasn't turned up for pre-arranged appointments and meetings and there has no been no reported sightings of him.
"There were no signs that he was depressed or may wish to harm himself. He seems to have vanished.
"His family are desperate to know what has become of him and they are being supported by a specially trained police officer.
"We want to hear from anyone who may have seen Mark or has any information about where he maybe."
Mark is described as white, 5' 9", clean shaven, with a tanned complexion and of stocky build. He has blue eyes and is bald.
Ring police on 101 or email firstname.lastname@example.org quoting Operation Light or contact the independent charity Crimestoppers anonymously on 0800 555111.