A police investigation into the death of Josh Clayton has concluded as not suspicious.
Josh disappeared after a night-time party in September 2015 and his body was found 10 days later.
Detective Superintendent Steve Parker, from Devon and Cornwall Police, said: "We have now concluded our investigation on behalf of the coroner.
"We have kept an open mind throughout the investigation.
"No suspicious activity was found and no suspects were identified.
"We have kept the family informed throughout this process and they are aware of the outcome of the report.
"The file has now been submitted to the coroner."
The initial inquest into his death was put on hold after new evidence came to light.
Josh's mum Tracey told ITV News Westcountry: "Their conclusion is that Josh walked home in pitch black round the east side of the island and fell in the sea and this is a very strong swimmer and a very strong diver.
"I think it's more likely than not that something has happened to Josh with the involvement of a third party".
Tracey continued: "We'll have to find other ways of trying to find out what happened to Josh.
"But the thing is, he went to a sleepy island for the second season and he didn't come home."