Why have Metrojet refused to release the cargo manifest? This only raises suspicion that something was being carried as cargo that should not have been, and that that cargo posed a potential explosive threat?
Alternatively, could something potentially explosive have been sneaked aboard in the cargo at SSH, that was not listed on the manifest?
From here on in, Russian and AB investigators are going to be very reliant on the thoroughness of the scrutiny of the airport security and the CCTV records, by Egyptian authorities.
This is not something that encourages reassuring thoughts about how any security breach, if discovered, will be treated.