The private detective hired by Madeleine McCann's parents has claimed that the youngster could be back with her family by Christmas.
Francisco Marco told a Spanish newspaper he knows who has taken the four-year-old and is putting together information for the police so they can make arrests.
The private detective insists the missing four-year-old is alive and being held by paedophiles in Spain, Portugal or north Africa.
Marco, boss of the Metodo 3 agency, said: "I hope she'll be back with her parents before Christmas.
"We have proof of her movements after her kidnap and we know she was alive the day after her disappearance. We are not certain she left Portugal.
"I talk of certainties because we know which group may have her or could have kidnapped her to then sell her on to others. We know who kidnapped her.
"In principle we're talking about paedophiles. One of the things that makes us believe Madeleine is alive is every day she's worth more to them. A professional kidnapper would have done something with Madeleine by now. He would have given her back or left her.
"I cannot say who she is with because we are putting together conclusive proof we can present to the authorities so they can proceed with their arrests.
"God willing, I hope that she will be back with her parents before Christmas."
The detective said that his own children keep him obsessively battling away at the case.
"It's the highest pressure case I've ever had to deal with because of the press and because of my own family. When I get home at night, my children ask me, 'Have you found Madeleine yet daddy?'"
Madeleine disappeared from the family's holiday apartment in Praia de Luz in Portugal on May 3. Kate and Gerry McCann left Madeleine and her two siblings in the apartment while they dined with friends. When they returned Madeleine was missing.
They have been declared suspects by Portuguese police. However Marco rejected any suggestion that the McCanns could be involved in their daughter's disappearance.
Marco said: "You only have to spend five minutes with them to realise theyve got nothing to do with this."
The McCanns' spokesman Clarence Mitchell said that the family was " pleased" the agency was so confident.
He said: "Metodo 3, the private detective agency we are employing to help find Madeleine, retains our full confidence.
"Clearly Kate and Gerry are kept informed of all major developments, though they are not informed of every twist and turn in the inquiry day to day."
The Find Madeleine campaign pays the Metodo 3's £50,000-a-month bill.