COPS searching for Madeleine McCann believe their prime suspect may have taken pictures of her and buried them.
German drifter Christian B is alleged to have taken twisted “trophies” from victims — though it has never been publicly confirmed if any exist of Madeleine.
German officers investigating Christian B believe hidden USB drives could hold clues to Madeleine McCann’s disappearanceCollect
Christian B is currently in jail in Germany for the 2005 rape of a 72-year-old American woman in Praia da LuzEnterprise
Detectives have been digging for USB drives hidden by suspect Christian BSolarpix
It has emerged detectives had specifically hoped to find data drives or USB sticks when they dug around Arade reservoir in Portugal in May.
None were found in the area where he camped and no forensic matches are expected — but officers think Christian B had a string of other hidden lairs.
The Sun has also learned investigators have received no new tip-offs or leads for months.
A source said: “They now know Christian B buried data carriers like hard drives and USB sticks at any of the places where he’s stayed so that was their real hope at the lake.
“They really thought they might find pictures there, but they are not giving up hope.
“They believe he made duplicates because he loved to keep them like trophies.
“So cops are now trying to find out more about Christian B’s movements.”
German police were criticised for sending Christian B a subpoena in 2013 asking him to account for his whereabouts when Madeleine, then three, disappeared during a family holiday in Praia da Luz in 2007.
Experts said it would have given the convicted sex offender a chance to destroy evidence.
However, officers have established he was so obsessed with his collection of vile images that he made duplicates — and may have overlooked a stash.
A source close to the case said: “They fear it’s the last chance to clarify Madeleine’s fate — and if they don’t seize it, there won’t be a second.
“It is not like cops are getting that many more leads and tip-offs.
“They have already worked through the most promising leads.”
It also emerged that 55-year-old parents Kate and Gerry, of Rothley, Leics, have been kept in the dark over the German probe because they are considered witnesses.
The source added: “The family was only informed one day before officers went public about Christian B.
“Other than that, they have had no briefings or updates whatsoever.
“As far as the Germans are concerned, the McCanns are witnesses — completely normal witnesses, as in other cases, and they know no more or less than anyone else.”
Christian B is currently in jail in Germany for the 2005 rape of a 72-year-old American woman in Praia da Luz.
Prosecutor Christian Wolters said: “Clearly finding any pictures of Madeleine would represent a huge step forwards.
“We are not commenting further at this time.”
Christian B’s lawyer declined to comment.
Earlier this week the McCanns finally received an apology from Portuguese police for initially making them suspects.
Always on move in van
DRIFTER Christian B lived in a VW T3 Westfalia camper van and drove around Europe until 2015.
Detectives believe he visited the remote Barragem do Arade reservoir in the days after Madeleine vanished.
In the following months he is thought to have stayed in the Villa Bianca in the Algarve village of Foral.
Around the same time he also had stints living in the German city of Dresden and Augsburg in Bavaria.
He also visited Sylt and Munich.
From 2012 to 2014 he lived in Braunschweig, Germany.
In 2015 he briefly returned to the Algarve and sold the camper van.
Gerry and Kate McCann have been kept in the dark by police as they are considered witnessesPaul Tonge