Police investigate Madeleine 'sighting' in Malta

Local television said the reports were made by tourists on Saturday in Valletta.

A search in one location had proved fruitless but police were keeping a closer eye on departures from the airport and Valletta harbour.

The reports come as a pickpocket stole treasured pictures of missing Madeleine from her father.

Gerry McCann was in London for a brief visit and withdrew £100 from a cash machine moments before the thief struck, lifting his wallet from a back pocket and running off.

The three pictures of Madeleine and her brother and sister were in the wallet along with cards and the cash.

They have never been seen in public and there are no copies.

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Susan Healey, mother of his wife Kate, said it was "yet another kick in the teeth".

She added: "Gerry is not clear exactly how his wallet was stolen.

"He did not see them take it. It contained precious photographs which have now been lost forever."

Mr McCann's sister, Philomena McCann, branded the thief a "dirty animal".

She said: "Gerry was at the bank to get some British currency, because he didn't have any at all.

"He took out £100 from a hole in the wall machine, put it in his wallet then popped it in his back pocket.

"He bent down to put something in his rucksack and some dirty animal had the wallet out of his back pocket.

"We don't care about the money, but we do care about getting the pictures of Madeleine back.

"There were three pictures, special ones that Gerry always kept with him, showing Madeleine and the twins.

"They were his favourites, really treasured pictures. How can you do that to someone who's been through what he has?

"He's already demoralised enough and to be put on the back foot like this, you can't believe some people can stoop so low.

"He's desperate to get them back. He's not bothered about the money. He'd just like whoever stole them to hand them back because they're precious to him.

"The whole family have been overwhelmed by the support and affection from all around the world, but it takes just one rotten apple to bring you down.

"I hope whoever took the wallet is so ashamed when they realise what they've done that they get those pictures back to us as soon as possible."

Mr McCann, 39, was pickpocketed at a cashpoint at Waterloo station in central London after arriving in the capital on Tuesday for a two day visit to interview candidates for a campaign manager to help keep Madeleine's profile high.

He was forced to delay the series of meetings he had planned while he cancelled his credit cards.

Mr McCann, a consultant cardiologist, had earlier come to the rescue of a fellow passenger who collapsed during his easyJet flight from Portugal to Britain. The man, who has not been named, needed a full medical assessment on arrival in Gatwick and was taken by ambulance to hospital.

But his sister said Mr McCann had been typically modest about the help he provided.

She said: "Gerry spends his life looking after other people so in a situation like that, you just go into your natural modus operandi and help.

"It's what you're trained to do, it's who you are. He didn't make a big deal out of it because it's the kind of thing that he does all the time at work."

The trip to London was only the second time Mr McCann has returned to the UK since Madeleine was kidnapped.

He arrived back in Portugal to be reunited with his wife, Kate, and the couple's two-year-old twins, Sean and Amelie, who had stayed in Praia da Luz, the resort town where Madeleine disappeared 49 days ago.