It might not be the only evidence the police have.

"Intercepted telephone calls and emails between the McCanns and their friends have "confirmed the death of Madeleine" say police, according to one Portuguese newspaper today. The intercepts are said to have been made in a joint operation conducted by Portuguese and British police officers.
Diario de Noticias reports investigators have already concluded that the missing four-year-old was killed in the apartment where she slept in Praia da Luz.
It says that Maddy's parents, Kate and Gerry McCann (right), and their friends who were holidaying at the Ocean Club, will be brought in for further questioning. Police are awaiting new tests from the McCanns' Renault Scenic.
According to another paper, Jornal de Noticias, police want to examine inconsistencies in the statements of Kate and Gerry McCann, who were interviewed separately late into the night early on in the investigation. In particular, they want to focus on a three-hour period in which only the McCanns saw Madeleine.
Respected news agency Lusa quotes one police source saying that they think "there's light at the end of the tunnel" and that the authorities have "an idea of what could have happened" to the four-year-old.
Police have known "for a month" that Madeleine had died in the apartment, it is widely reported. The tabloid newspaper 24 Horas says that the police are looking for Madeleine's body in the sea, helped by English sniffer dogs. They have intensified searches around the nearby town of Lagos and along the Algarvian coast, it says.