Marc went to the Maresfield area on Saturday evening (29 May). He called his family about 11.30pm to say he was on his way home but never returned. Sadly, detectives now believe Marc may have come to harm.
A 19-year-old man was arrested on suspicion of his murder at a property in Eastbourne on Tuesday (1 June). The suspect remains in custody for questioning.
Detective Chief Inspector Alasdair Henry said: “Sadly, we are now treating the disappearance of Marc Williams as a criminal investigation and a suspect has been arrested on suspicion of his murder.
“Finding Marc remains our priority and we continue to appeal to the public with any information to please come forward and report it to us.
“Our thoughts are with Marc’s family at this incredibly difficult time and they are being supported by specially trained officers.
“This investigation is a dynamic and fast-moving enquiry and our officers are working around the clock to establish the circumstances of this incident.
“We thank the public for their patience as we continue to carry out our work in the area.
“This incident is being treated as isolated and there is nothing to suggest any threat to the wider community.
“Anyone with information that may assist with our investigation is urged to report it to us immediately online or by calling 101, quoting Operation Skittle.”