Portuguese detectives are investigating a trip Kate and Gerry McCann made to Spain, it has emerged.

A day after a possible sighting of four-year-old Madeleine was ruled out, police re-focused on her parents, who are formal suspects in her disappearance.

They are believed to be studying CCTV footage of their journey to Huelva, across the Spanish border on August 3 where they went to raise their daughter’s profile.

It is understood police are suspicious of the trip because the McCanns changed their plans at the last minute and did not have any formal meetings while there. Detectives are said to be working on the theory, dismissed as ludicrous by the McCanns, that Mrs McCann may have accidentally killed her daughter and relied on her husband to help cover it up.

One line of inquiry is whether they could have hidden her body and used their silver Renault Scenic -hired 25 days after she disappeared - to dispose of the body. Traces of Madeleine’s DNA were allegedly found in the vehicle.

Police are puzzled by the high mileage, with 1,700km added to the clock between May 27 and July 3. They are sceptical about the Spanish visit because the couple did not arrange any meetings with dignitaries and two hours are unaccounted for, it was claimed. A

police source told Portuguese newspaper Correio da Manha: "The trip to Spain on a national holiday raised suspicion and investigators have been to the country trying to find out where the McCanns went."

The couple’s spokesman Clarence Mitchell insisted the journey was innocent: "The trip to Huelva was organised on behalf of the Find Madeleine Campaign.

"It was conducted in the full glare of journalists from all over Europe and beyond. Kate and Gerry McCann are entirely innocent and have nothing to hide."

It is less than 24 hours since a little girl with striking similarities to Madeleine in Morocco was identified as Bouchra Ben Aisa, a farmer’s daughter. There were concerns that the authorities were slow to act after she was traced by journalists rather than police.

A source close to the couple said: "Frankly it is a sign of the times that journalists can locate a relatively obscure child in the Moroccan mountains and one would hope that the authorities were able to locate a child as quickly as that."

But Mrs McCann’s aunt Janet Kennedy said the McCanns were "philosophical".

"Inevitably it is a disappointment, but I think they are very philosophical about it because it’s happened so many times.

"Just suppose Madeleine is in Morocco, what does that mean? You just have to keep on."

Mrs Kennedy spoke as she helped parcel up more than 2,000 toys and gift given to the McCanns which they have decided to send to underprivileged children in Belarus.

They were left at the war memorial near the family’s home in Rothley, Leicestershire, alongside thousands of green and yellow ribbons.

They will be sent to Zhodina, some 20 miles from the capital Minsk, and Bobrusk in the south of the former Russian republic, next week.

The family has spent nearly £300,000 of the fund set up to help find Madeleine, which has now raised £1,041,697.