A team of British forensic analysts are expected to join DCI Andy Redwood and his team of detectives in Portugal this week in a renewed bid to uncover the truth behind the disappearance of Madeleine McCann.

Portuguese police sources told the Guardian that the scientists have asked to revisit some of the evidence retrieved from the holiday apartment from which the British toddler went missing on 3 May 2007. The forensic evidence gathered at the time of Madeleine’s disappearance has been stored at the National Institute for Legal Medicine and Forensic Sciences in Coimbra in central Portugal.

Detectives and forensic technicians from the Metropolitan police are scheduled to visit the laboratory on Wednesday.

Detectives led by Redwood will meet with their Polícia Judiciária counterparts in Faro on Tuesday to discuss the request.

Police said they had not yet received any official orders from the public prosecutor’s office and that the next phase of the investigation was unlikely to commence for at least a fortnight.

A source close to the case told the Guardian that the request appeared “to focus primarily on the further questioning of some of the suspects brought in by Faro police in the summer”.

In July, Portuguese police quizzed four Portuguese nationals who were declared arguidos, or formal suspects. They also spoke to 11 witnesses.

The questioning of these suspects followed the end of major ground-level searches in Praia da Luz in early June, when Scotland Yard detectives scoured a large patch of scrubland.

The force described the operation as the largest overseas deployment ever undertaken by British police, and said it was the “first phase of this investigation” into Madeleine’s disappearance.

Although the searches turned up no fresh evidence, the Met said detectives had gained an “essential understanding of the activity for which people have used this piece of land” and alluded to “substantial work which is yet to be done in the coming months”.