John Darwin was not interviewed by detectives immediately after his reappearance because, said police, they wanted to give him and his family time to get over the shock. But yesterday morning, officers were banging on the door of his son's home in Hampshire demanding that Mr Darwin come out.
A dishevelled Mr Darwin was then arrested and escorted to a waiting police car. It was yet another bizarre twist in the captivating tale of the former prison officer who disappeared five-and-a-half years ago only to reappear at a police station last Saturday, declaring: "I think I am a missing person".
His arrest coincided with the startling emergence of a photograph from a Panamanian website which appeared to show a beaming Mr Darwin looking fit and well next to his "widow" Anne in July last year.
Only hours earlier, his wife, Anne, 55, had spoken of her amazement at her husband's return. Along with her sons Mark, 31, and Anthony, 29, they explained that he had no memory of the past seven years and that his return was "traumatic and emotional".
Detective Superintendent Tony Hutchinson said Mr Darwin, 57, had been arrested on suspicion of fraud at his son's home in Basingstoke. He was returning to the Cleveland area last night for questioning.
Det Supt Hutchinson said: "There will be people out there who will know where he has been, where he has been living and what he has been doing. We want to hear from them. It may well be he has been living abroad, he may well have been known by another name.".
Mr Darwin disappeared in March 2002 after setting out to sea in his kayak. His empty kayak was washed up some time later and a massive search failed to find a body. An inquest was held in Hartlepool 13 months later, at which the coroner, Malcolm Donnelly, declared him dead and recorded an open verdict.
But, if his disappearance had been dramatic, his reappearance was simply astonishing. Mr Darwin turned up at a central London police station last Saturday evening looking, officers said, "tanned, well-nourished and well-dressed".
Stories emerged of applications for credit made last year in his name and rumours circulated that he may never have left his home in Seaton Carew. Many neighbours were adamant he would have been spotted had he remained in the area.
Then questions were raised about the fact that only six weeks earlier his wife had sold the family property for a reputed 500,000 and moved to Panama without, some neighbours claimed, saying goodbye or leaving a forwarding address. There were reports that police had been tipped off three months ago about a possible link to Panama a tax haven, usually overlooked by tourists and with an expatriate community of 1,000 Britons.
Mrs Darwin insisted in an interview that "it was not the money I ever wanted it was having my husband back". She had claimed on his life insurance, she said, but had done so in good faith. She had not rushed home to be reunited with her spouse, she explained, because of certain issues regarding her Panama visa and the arrival of some furniture.
"As soon as everything is sorted out, of course, I'll be straight back," she said.
The picture on the Move to Panama website, if it is genuinely Mr and Mrs Darwin, suggests they were in contact long before the telephone call that she said she received from her son on Saturday night, telling her that her husband was alive. Mario Vilar, a property agent, said the couple had been happy to be photographed alongside him when they rented a room from him.
Det Supt Hutchinson said police were checking the validity of the Panama photograph and were looking to speak to Mrs Darwin.
"Obviously Mr Darwin's reappearance has raised a lot of questions and created worldwide interest," Det Supt Hutchinson said. While the UK has an extradition treaty with the Central American state, it would still be a lengthy process, he said. "It's not simply a case of jumping on a plane and making inquiries."
Det Supt Hutchinson said police received a tip-off three months ago about the couple's finances. "There was some information to suggest that perhaps there was something suspicious with regard to his disappearance. As a result of that information, we then began to conduct some inquiries."
He added: "It's only right and proper that we speak to him under caution and we speak to him after he has been subject to various medical examinations.
"Without doubt it is an unusual case."
Why did John Darwin turn up at a London police station six days ago?
His arrival in London came shortly after British police began reinvestigating his case. A private investigator had been seen outside the new home in Panama City of his wife, Anne, possibly alerting her to enduring interest in her husband. Mr Darwin, 57, is undergoing medical tests to ascertain whether his amnesia is genuine or part of what police suspect could be a fraud. Flight records from Panama last week are being checked.
What will happen to his wife?
Interpol said yesterday it has not been contacted by British police but the Cleveland force confirmed that Anne Darwin, 55, could be interviewed in the future.
What would extradition from Panama involve?
No Briton has ever been extradited from Panama. If British detectives wanted to interview Mrs Darwin in Panama, they would be expected to provide prima facie grounds for suspicion. The process could take six months.
Why did Mrs Darwin move to Panama?
There are many retired people in Panama. It has cheap property and is a tax haven.
Why were police investigating Mr Darwin's case just before he reappeared?
A credit card was applied for in his name, using his personal information, in March 2006.
Will the family have to pay back the insurance money?
If there is evidence of fraud, insurers can launch legal action to reclaim a payout. The Association of British Insurers said it would expect a claimant to inform a company of a change in circumstances and reach a settlement. Illegal claims would be investigated by police.