Kate and Gerry McCann said since their daughter disappeared in Portugal May 3, 2007, days before her fourth birthday, they have spent a fortune attempting to find her, The Daily Telegraph reported Saturday.
Despite the fees paid to the Metodo 3 detective agency, the McCanns say there is no limit to how much they will spend.
"We can't set a limit. A child does not have a price. We will pay what we have to. It just takes one person to make the one phone call we so hope for," said Kate McCann, 40.
"We want to find her alive. But if she is dead we want to know. There's nothing in the police report that indicates anything bad has happened to her."
Meanwhile, Gerry McCann has criticized police officials, particularly detective Goncalo Amaral, who accused the couple in the disappearance of Madeleine from the Praia da Luz resort, the Telegraph said.