A mystery is prime suspect Efits hidden for many years. A mystery is why there were more regular checks on the night she disappeared. A mystery is why the parents didn't call the police straight away knowing she had been abducted. A mystery is deleted mobile log history within 24 hours. A mystery is paedo gangs being blamed within a few hours of her disappearance by a witness. A mystery is a key turned into not a key. A mystery is a timeline that doesn't add up. A mystery is parents not answering ALL questions to move the investigation forward. A mystery is CC being washed. A mystery is a car boot that was always seen open. A mystery is the Smiths saw long sleeves. A mystery is a twin reported to say Maddy's jammies. A mystery is getting keys to the local church. A mystery is certain statements not seen by Amaral. A mystery is Pamela Fenn hearing crying for 75 minutes when the parents claim they were in the apartment. A mystery is why Madeleine said why weren't you there when WE cried last night and they went out again and left them alone. A mystery is how Tannnerman kept changing and morphed into George Harrison. A mystery is how Jane Tanner passed two men without being seen. A mystery is fingerprints found on the window. A mystery is the cleaner seeing a cot in the parents bedroom. A mystery is many dog alerts. A mystery is parents not being present at first time Madeleine sailed (she cried). A mystery is why they were the only ones missing from the group at the beach. A mystery is a visit that doesn't add up. A mystery is a moving ajar door. A mystery is Kate sleeping in a spare bed for the first time. A mystery is the first visual check of the week on Madeleine (last time seen) in an unsecured apartment.
A mystery? No just questions that have answers.
There is no 'mystery' other than that created by the false premise inherent in the question.
Nothing was 'withheld' for any length of time at all.
Rather, two efits, produced at, or around, the time of the shelving of the first enquiry required a second enquiry, and a fresh, full-scale police investigation to justify their release, which is precisely what happened, when Scotland Yard, themselves already in possession of the efits before
they released them, chose the moment of the
Crimewatch programme to do so.
All other speculation is idle (at most charitable);
malicious (at probably more accurate) tittle-tattle.