Did I miss something, or is Juge Roban written out of season 4? It's so long since I watched season 3 I forget what happened to him. Odd thing is, he's on the cast list for the first three episodes on IMDB but I don't recall seeing him.
After his brother turned out to be as bent as a 9 Euro note at the end of Spiral 3 Roban was taken off the case. This, added to the fact that the young lawyer who might have been his son topped himself could well have led to Roban taking a leave of absence.