Is there a secret witness to the disappearance of Madeleine McCann

An employee at the Portuguese hotel where Madeleine McCann vanished from a decade ago may know what happened to her.

The lead is the newest in the search for the missing British girl, who was four when she disappeared from her parent's holiday apartment in Praia da Luz while they dined nearby in April 2007.

Read more: Secret network of 'caves': Ex-police chief's latest Madeleine McCann theory
Scotland Yard police officer Colin Sutton revealed to Sunday Night evidence suggests a worker at the Ocean Club Resort could solve the case.

"There is an employee, somebody who worked within the Ocean Villa complex who has some information or some knowledge that may be of assistance," he said.

It is unknown if the employee is female or male, but a search for them is underway.
The Scotland Yard, who took over the investigation from Portuguese police in 2013, was given more than $140,000 (AUD) in March to look into the lead and fund inquiries for another six months.

The revelation comes just days after a minder who cared for Madeleine claimed the Ocean Club Resort was dangerous.

The woman, who was not named, told The Mirror the resort was considered so unsafe the nannies who worked there were given rape whistles, writes the Daily Mail.

She also claimed they were told not to walk around alone.

The disappearance of Madeleine has been shrouded in mystery since she vanished a decade ago.

It has been pondered if the child wandered off and had an accident or if she was taken in a burglary gone wrong.

Mr Sutton said he has come up with five plausible theories to explain Madeleine's disappearance.

The detective claimed she could have been taken by a paedophile or she could have been snatched by a trafficking gang to replace a dead child.

Although the area near where she was last seen has been ransacked by police for any trace of her, Mr Collins said it would be 'almost impossible' to find her body, if she is dead.

"It's a large area of very low population, of scrubland, of ancient wells."

"There are areas there where, you know, humans probably don't go, from one year - or one decade, even - to the next."

In the weeks before Madeleine disappeared, witnesses reported seeing people loitering in the area.

One schoolgirl even reported seeing a man looking at the McCann's resort apartment.
There were two burglaries at the resort just before the family arrived, officers told Sunday Night.

Madeleine's parents, Gerry and Kate, told the Seven Network program they did not have anything to do with their eldest child's disappearance.

Just four months after they frantically discovered her bed empty, Gerry and Kate were named the prime suspects - a claim they vehemently deny.

"No. No, never. And you know, there's nothing with any logic that could, you know... You would have to start with why, you know? How? When? Who? And there's just simply, you know, no answer to any of these things," Gerry said when asked if he killed his daughter.

Detectives have released composite images of what Madeleine would look like now at the age of 14 to help progress the investigation.