we've been doing it on our own. >> but kate and gerry mccann weren't giving up. will help the search directly and indirectly. >> kate mccann's book was really a cry for help. but in the end it included a plea, a plea to reopen the case. >> thank you very much. >> a plea the mccanns would aim next at britain's prime minister. >> in a letter printed in one of the big tabloid newspapers in the uk, they essentially begged prime minister cameron to open up a review of the case. >> i believe there are bits of information that haven't been linked up to each other which could then be significant. >> and in the end, david cameron did respond within 24 hours of the mccanns' open letter appearing in the press. he had authorized the metropolitan police to undertake a review of the case. >> in 2011, scotland yard ordered a review called operation grange. their task, to assume nothing and reexamine the entire case from the very beginning. less than two years later, that review launched an official investigation. in the summer of 2014, officials returned to praia da luz to cond