The new Madeleine McCann search will not just cover old ground

The police are not just covering old ground.

The main difference is that the police are not just working from the crime scene, but also tracing back from a possible suspect, Christian Brueckner, as well.

This results in a different investigation entirely and the importance of this is often overlooked.

However, the ex-chief inspector warned the Mirror that the chance of a breakthrough is relatively small.

The new search for Madeleine McCann is being carried out between 2-6 June.

The search will restart near the area where the 3-year-old went missing 18 years ago.

But, this time the area encompasses Praia da Luze and a house near the holiday resort, where the principal suspect, Christian Brueckner, used to live.

Detectives investigating a serious crime are usually engaged in what's called a reactive investigation, which follows certain lines of enquiry.

Reactive investigations generally tend to focus on the crime scene, seeing that at least some part of the crime must have happened there.

Though from the moment they suspect someone of committing the crime, detectives can focus on lines of enquiry following from the suspect as well.

Due to the suspicion of Christian Brueckner, the new search will include new locations connected to him in some way as well.

During previous searches, the investigators were unaware of Brueckner as a significant suspect, so they had no reason to search locations connected to him.

This implies that the current searches are not just the police going over old ground in case they've missed something previously. This time, there is a bigger chance of finding something new, or even something confirming the police's suspicions about Brueckner.

Naturally, officers will still take the opportunity of revisiting some areas searched previously with less effective equipment compared to the latest equipment they have available for this new search.

A Portuguese source said the main goal of the search is to find Madeleine's body.

However, former Met Detective Chief Inspector Peter Kirkham remains rather pessimistic, per the Mirror, when asked if the searches will finally find some trace of Madeleine and explain how and why she disappeared.

He goes on to explain that the suspicions about Brueckner fall short of being any sort of proof of his involvement.

Even more important, it is still not known what happened to Madeleine that night. There are still several possible explanations that cannot be ruled out, even after almost twenty years of international investigation.

Madeleine vanished 18 years ago while on holiday with her family.

She would have celebrated her 22nd birthday last month.