The head of the Portuguese CID admitted yesterday that he had no idea what had happened to Madeleine McCann since she disappeared 106 days ago.

Alípio Ribeiro, the director of the Polícia Judiciária, said he was still optimistic that his officers would discover the missing girl’s fate, although he said that she was most likely to be dead.

Mr Ribeiro admitted that officers had not warned Madeleine’s parents, Kate and Gerry McCann, before saying that they now believed that Madeleine was probably dead. “They are being informed of what happens, but it is a very dynamic investigation,” he said. “We work with many hypotheses. We cannot explain to them everything we are investigating.”

The Times revealed yesterday that Portuguese detectives had been told that traces of blood found in the bedroom from where Madeleine was abducted were not from her.

A senior Portuguese police source confirmed: “We have been informed that the blood was from a man.”

The news appeared to give fresh hope to Mr and Mrs McCann, who thanked the thousands of people who supported them during accusations that blood proved that their daughter had been killed in her bedroom.

“Over last weekend alone they received 7,000 e-mails of support and countless letters of support,” a spokeswoman said.

However, Mr Ribeiro said that his officers were not close to discovering what happened to Madeleine after her disappearance from a holiday apartment at the Ocean Club complex in Praia da Luz. “We have no idea where Madeleine could be,” he told El Mundo newspaper in Spain. “There is a long road ahead and it would be very frivolous for me to say that we are close to the end.”

He insisted that progress had been made: “We are not where we were at the start. If I say I’m optimistic it’s because I think we will end up understanding what occurred. If we weren’t optimistic, we would not have the courage to advance. This is a very complex case.”

Mr Ribeiro said that while the belief by police that Madeleine, from Rothley, Leicestershire, was most likely to be dead, as revealed in The Times on Wednesday, “is a strong hypothesis, we cannot say she has died. It is on the table and it is necessary for us to analyse it.”

He insisted again that Madeleine’s parents had never been considered suspects in her disappearance on May 3, shortly before her fourth birthday. He also said that contradictions in the statements from the three British couples and the woman who were on holiday with the McCanns were “worth little”. The fellow holidaymakers are likely to be interviewed by police again. The couples are Russell O’Brien and Jane Tanner, both 36, from Exeter; Fiona Payne, 34, and her husband, David, from Leicester; and Rachel Oldfield, 36, and her husband, Matthew, from London.

Mr Ribeiro said. “We are working to clear up a difficult situation. Especially as concerns the motive. It could have been for money, for revenge, for crime or hatred. We don’t know.”

He criticised some of his officers for leaking information that led to false media reports. “The police should be discreet, but there is always someone who talks,” Mr Ribeiro said. “Sometimes it is someone who knows nothing and just wants to be a protagonist.”

Scientists at the headquarters of the Forensic Science Service in Birmingham are continuing to carry out tests on items discovered in the McCanns’ apartment and in other areas. They are also carrying out further tests on the traces of blood discovered by British sniffer dogs in the apartment.

Times Recommends

• It’s only Brits who don’t appreciate me, says Blair
• Party’s over for Greek graspers
• White House tightens security for Xmas marathon