For me :
- As stated here : -
New lead German cops probing Maddie suspect is revealed to be phone records
“The feeling among Portuguese officers is that Christian B isn’t the man who took Maddie.
I think that as stated the PJ still doesn't believe that CB is the responsible for MM crime as BKA didn't provide the secret evidences + new evidences, etc so for the PJ "something else" did happen to MM like GA theory. Unless BKA/HCW can make PJ change their mind I don't think that PJ will co-operate much as well on regard to the MM case. Goes without saying that as mentioned on some articles already they will fully co-operate in attempt to get CB charged with the other 3 cases like the Irish rape, etc.
- SY/MET/Operation Grange most likely don't have BKA secret evidences as well so they can't do anything about CB. They still want to show that they are doing "something" if not for anything else to justify the costs of Operation Grange and request more money so they are after MN in hope that he does "know something" MM related even if the chances of him to be involved on the crime are close to 0. They also need to show something to MM parents as they are the police force that are "closer" to them, meaning they will follow their will to search for a living MM unless someone like BKA can indeed show something that without doubt shows that she is dead.
BKA FOR ME is in a bad position as they need full PT co-operation to search on PT for possible MM body and/or more evidences but they don't want to share the info that they have (or at least initially they didn't do so even if now they are stating on the papers that they will reveal all of it on the next meeting in Portugal).
For me the old secret info are all that we already know + witness statement about some possible CB confession with details of the crime and/or something indirect like interception of text/calls that links CB to MM.
The NEW evidences/pieces that they are talking about now most likely are related to behavior examination of CB actions related to MM case, in other words actions that CB did made related to MM case that match actions that he did make on crimes that he is guilty for (and/or don't match actions under same circumstances on crimes he was cleared out).