No, he did kill her but the investigation was so mismanaged that it’s impossible to prove. Her mother discovered later that the police chief was Joran’s godfather and did everything in his power to sabotage the investigation.
She wrote a book about it and it’s really disgusting how they treated her and her family. I just listened to a podcast about this case by two sisters that knew her and were in school with her (People are the worst).
Edit: the extortion was an operation by the police and her mother to get him to confess, since he was already asking her for money to tell her where he buried her or how he killed her. (I think)