Madeleine McCann's friends and family may have destroyed vital evidence in the first few hours after her abduction, Portuguese police have said.
Chief Inspector Olegario Sousa said so many people crowded into the room where she was taken, it was proving difficult for the forensic teams. He said their well-meaning actions could prove "fatal" for the investigation.
The police officer's comments came as Kate and Gerry McCann marked 45 days since their four-year-old disappeared with no breakthrough in the case.
A source close to the family described his words as "very unhelpful".
Mr Sousa, a spokesman for the Policia Judiciara, said more than 20 people had gone into the McCann's Mark Warner holiday apartment on May 3, the night Madeleine disappeared.
Among them were friends, family, other holidaymakers and staff from the Ocean Club resort who touched furniture and opened and closed doors.
He told Portuguese newspaper Diario de Noticias: "The presence of so many people - especially in the room where the little girl slept with her brother and sister could have at least complicated the work of the forensic team.
"At the very worst they would have destroyed all the evidence. This could prove to be fatal for the investigation."
DNA samples have been taken from the bedroom and sent to three forensic laboratories in Lisbon, Porto and Coimbra - part of the Instituto Nacional de Medicina Legal (INML).
On June 1 a source at the laboratory revealed DNA samples of a "stranger" had been recovered from the room. Police are still waiting for further results.
