A detective who spent three years working on the case of missing British toddler Madeleine McCann says he is convinced she may still be alive.

Detective inspector Dave Edgar, who was hired by the family to look into the disappearance early on in the investigation, claims child sex traffickers are most likely behind the abduction and that it was carefully planned. Mr Edgar, who handed his files over to the Metropolitan Police in 2011 but has stayed abreast of developments in the case, says research shows kidnappers often confide in someone close to them and urged anyone with information to speak to the police. Speaking ahead of the tenth Mother's Day since Madeleine vanished, aged three, from a holiday apartment in Praia Da Luz, Portugal, Mr Edgar said his work on the case led him to believe that a lone kidnapper or gang is responsible for the abduction and appealed to them to share anything they feel may be useful in uncovering what happened to Madeleine, who would turn 14 years old in May. Edgar said, ‘If anyone confided in you, now is the time to come forward. They can’t keep it to themselves and research has shown they always confide in someone else.’ Mr Edgar also addressed claims that Madeleine's parents know what happened to her: "I was looking at everything and that would include them,” he told the Mirror. “If I found any evidence against Kate and Gerry I would have given it to the police immediately. Kate and Gerry would expect no less. But I found no shred of evidence. “We obviously look at all factors – motive, preparation, opportunity – and there was absolutely nothing.” Mr Edgar believes she may still be alive and may be held by her abductors. Earlier this week, Kate McCann was forced to defend herself against claims that she profited from the sale of her book about her daughter's disappearance. “For those posting that we are trying to make money, you are absolutely wrong.” she posted on Facebook. A representative for the Facebook page Find Maddie said that an advance Kate McCann had received for the book went towards the fund that pays for the continuing search for Madeleine.