Gerry McCann is convinced his daughter's kidnapper was hiding behind a door in their holiday apartment as he checked on his sleeping children, according to a friend.

The cardiologist saw all three of his offspring – Madeleine, and the twins Sean and Amelie – sleeping peacefully at just after 9pm on the night of her disappearance.

But as he turned to leave the ground floor room, he noticed that a door which he thought he had closed earlier was slightly ajar.

Agonisingly, he is now sure that standing behind this door was his four-year-old daughter's abductor, waiting to steal her from her bed in the Praia da Luz.

The haunting memory was revealed by a close family friend, who said Mr McCann and his wife Kate, both 39, checked on their children as they ate at a tapas bar 40 yards away.

"Gerry believes there was certainly something odd," the friend said. "The bedroom door was ajar when he got in and he thought: 'That's strange'.

"He went into the room, checked that Madeleine was still asleep in bed; she was and he came out, closed the door.

"Initially he thought she might have got up and gone to the toilet or gone to get a drink or something but now he thinks that the abductor must have been in there hiding."

The friend said Gerry had pondered over the sequence of events that night for four and half painful months. "He believes the abductor came in, opened the door and didn't have time to close it (before Mr McCann arrived)," said the friend.

After Mr McCann checked the room at 9.05pm, friend Russell O'Brien offered to check the children. At 9.30pm, he listened at the door, but crucially did not go in. It was not until 10pm when Mrs McCann went back to the apartment, that Madeleine was discovered missing.

It is thought that when she went to open the door to check, a gust of wind from the open window in the room caused the door to slam behind her, sparking alarm.

The couple believe Madeleine's kidnapper came through the unlocked patio door facing the tapas restaurant and climbed out of the window at the front of the apartment.

Friend Jane Tanner said she saw a man carrying a little girl in pyjamas similar to Madeleine's at around 9.15pm. But as details of the night finally emerged, there was confusion over how the couple had spent the afternoon with Madeleine and the two-year-old twins.

A restaurant manager in Praia da Luz said the family were at the beach at around 5pm, while the couple insist Mr McCann was playing tennis as Mrs McCann gave the children supper at the Ocean Club resort, where they were staying.

Miguel Matias, who runs the beachside Paraiso restaurant said he saw Mr McCann dancing with his daughter as the family ate a meal on the terrace in the early evening.

Several days later he contacted police and handed over CCTV footage: "We would not have handed the CCTV if we were not sure. They have taken it as evidence."

A Portuguese police source confirmed the footage had been received but could not comment further because of the country's strict secrecy laws.

However, Mr and Mrs McCann insist witnesses saw them on the tennis court and at the Ocean Club restaurant with their children.

The last image of Madeleine was taken at 2.29pm of the little girl sitting by the side of the pool with her father.

A source close to the couple said: "Madeleine went to kids club in the afternoon, after the photograph was taken at the swimming pool. There are records for that, written records, and witnesses."

It is now 142 days since Madeleine disappeared and Portuguese police appear no closer to finding the little girl. Judge Pedro Daniel dos Anjos Frias has finished reading the 4,000-page dossier of evidence in the case from police, and handed the files back to prosecutors. No details of any rulings have so far been made public.

In Portugal, detectives were still waiting of the results of a toxicology report being carried out by the Forensic Science Services in Birmingham.