Just re watching eps 6 and 7.
In 6 you can see crease marks In a little round shape on the brown envelope ziane gives to Maliki.
And when they meet with the cleaner bloke in Brussels, the reason they don't demand the money back is that he does give them something to go on- he tells them he saw ziane pick something up. Baptistery knows ziane never submitted evidence so he's off following the lead to ziane.
And, in every episode, they show that bridge from several angles but always on way that to me is more then just a scenery shot. I am wondering if something happened on the bridge, maybe ollleh fell off it after escaping from or being released from whoever took him.