My personal semi-conspiracy theory on this is that the search warrant served on Keffals (no, not a SWAT call, a search warrant) contained some note that they got probable cause from evidence on a kiwifarms thread. Since then, Keffals has been running to countries with no extradition treaties to Canada and trying their hardest to erase that evidence from the internet under the guise of stopping suicides.
If the note references probable cause from a thread and the evidence is on kf, wouldn’t the authorities already have that evidence or be able to get a search warrant for it? Why would they search someone’s house for it?
Basically, they had the allegations and enough substantiating evidence to go to the point of looking for more evidence, but not to get all the way to an arrest/conviction. A search warrant is the next step.
EDIT: Also, the police have most likely downloaded the information, but you never know.
Now consider that Isabella's father Mike Janke is a former Navy SEAL who has a professional relationship with Matthew Prince, Cloudflare CEO:
https://www.youtube.com/watch?v=m1wio7sDDBA
These records have been wiped from the Internet Archive. I wonder how long they will remain on archive.ph.