I don't think it's appropriate for investigators to make much publicised claims about what the evidence tells them then still have failed to bring the case before the courts three years later.
I recall there was a leak involving a member of the public - Amaral, which identified the suspect. That's the guy whose misconduct of the case ended with him being sacked from it.
There are legitimate instances of police seeking information as a result. Who knows if that would even have been necessary without Amaral's Saunokonoko podcast interview when he flagged up Bruekner.
The information sought (not leaked) concerned phone numbers ~ vehicles etc
I am aware that Amaral did as you say "make much publicised claims about what the evidence tells them then still have failed to bring the case before the courts" Sandra Felgueiras blew the whistle on that one.
Good that you know that was an indiscretion at the least when one considers Portugal's "strict secrecy laws, possibly more than that.