German police say they have solved the mystery surrounding a young man who, for the past nine months, has claimed his name was Ray and that he had lived in the forests around Berlin for five years.

The English speaking youth told authorities in the German capital he and his father "Ryan" had lived together in the wild until his father died in August 2011, at which point he returned to the city.

He claimed he was 17, and asked for help.

However, police now say his story was a fabrication: "Two days ago, police published a photograph of the boy who called himself Ray, asking the public for help in identifying him," police spokesman Klaus Schubert said.

"We had to assume that somewhere out there, someone would know him, even if it's not in Germany but maybe in a neighbouring country. This appeal was a success and people called up from the Netherlands."

He went on: "This morning we confronted him and told him: 'You are not Ray but Robin from the Netherlands.' He immediately replied: 'Yes, that's true."

Authorities in the city are now considering whether to charge 20-year-old Robin for fraud, to try and reclaim damages for the expense of keeping him, and for the waste of police time.