The marine, 31-year-old Toby Studabaker, has been arrested in Frankfurt, Germany, on charges of abduction, police said.

Shevaun was reunited with her parents Stephen and Joanna Pennington at Leigh police station, near Manchester in northwest England.

Speaking later to Sky News, they expressed relief at their daughter's safe return.

"I was so glad that she was alright, back in one piece," said Stephen Pennington, 43.

Joanna Pennington, 42, broke down in tears as she paid tribute to the police.

They "have been absolutely fantastic. We could not have asked any more of them from the moment we reported her missing to this moment now."

She added: "I cannot tell you how relieved I am. It is such a turnaround from the situation days ago, which seems years ago. It is absolutely fantastic."

Shevaun earlier flew back alone to Manchester Airport from Stuttgart in Germany, via Amsterdam, and was greeted by British police officers.

Police originally said Shevaun had flown from Frankfurt.

Studabaker's arrest came after police sources revealed that child pornography had been downloaded from the Internet on to a computer used by the former soldier. The information had previously been withheld so as not to jeopardise the investigation, the sources said.

Police also revealed for the first time that they had evidence that Studabaker was aware of Shevaun's real age, despite his claims in calls to his family in the United States that he had thought she was 19.

German police confirmed that Studabaker was in their custody and that he had been arrested in Frankfurt on a request from British authorities.

German authorities were to determine whether Studabaker had broken the law in Germany and whether he should be extradited to Britain.

British police superintendent Peter Mason told reporters that the former soldier was arrested for abduction under the power of an international arrest warrant.

Announcing Shevaun's return to Britain, Mason told reporters: "I have great relief to inform you that Shevaun Pennington is safe and well."

Shevaun and Studabaker had flown from Manchester to Paris on Saturday after building up a year-long relationship over the Internet, according to British police.

Their disappearance sparked an international manhunt, bringing together British police, French officers, Interpol and the US Federal Bureau of Investigation (FBI).

British officers had also travelled to Charles de Gaulle airport outside Paris to meet their French counterparts.

Pennington, from Wigan, near Manchester, left home on Saturday, but contacted her parents for the first time only late Tuesday without offering any clue as to her location.

Mason said Shevaun had souned at ease during the brief phone call.

"There was no indication that she was under any duress. She was there of her own free will," Mason said.

He added that Shevaun had made a second phone call to her parents early Wednesday, during which she assured them once again that she was well.

Studabaker has been described as a devout Christian who attended a bible college in Ohio from 1993 to 1994. His wife Jenny died of cancer last year. The couple were childless, according to family.

Studabaker grew up in Constantine, Michigan, where he trained in martial arts and was a keen player of American football. He served with the marines in Afghanistan, for which he was decorated, but left the armed services in June with a shoulder injury.

WAR.WIRE