I presume that the investigators have authorised the somewhat barbarous dismantling that is shown in the pictures.
The assumption must be that they do not expect to learn a great deal from the wreckage. ie they already have a pretty clear idea of the cause of the incident.
I'm surprised to see this dismembering too. It looks more like disposal than careful dismantling.
A previous poster mentioned that Airbus had advised on the breaking up of the tail section, and I believe this was before the DFDR was found. So I think they decided on the sawing-up before they had any other evidence. Why would this be?