Acknowledgments
The greatest thanks belong to @JayeLTee , who discovered the leak, clearly recognised the severity and started the chain of events that led to the closure of the leak.
Special thanks to "Dissent Doe" of DataBreaches.net for reaching out to the Bozeman Police Department, who responded promptly by calling her to get IP addresses and details so they could investigate and follow up. They made contact with the state lab, who notified the police that they had just heard from the vendor and had unplugged everything while they investigated.
Thanks to the FBI and Bozeman PD for the prompt and professional contact. Beside them, no official that was contacted reached out.
I also wish to thank (in alphabetical order) Abraham, Andy, Ben, Cody, Dhruv, Emma, Frank, Harlo, Jeff, Jerry, JollyOrc, Judie, Royce, Russ and Rysiek for providing assistance. If I omitted someone, I apologise for the oversight. The communication turned into a frenzy on June 17th and some may have escaped the analysis for my PostMortem.
Closing Remarks
It is clearly necessary that we have at least one public contact in each country that investigates and closes data leaks reported to them. The effort to close even the worst leaks is unbearable and currently rests on the shoulders of security researchers and their supporting environment.
Time spent on this leak from my side (without the time for this report) is 12+ hours. My best estimate on the effort of all people involved closing this leak would be in the multiple hundreds of hours. The amount of time spent by the person responsible for the leaking system on security issues: None.
I assume the the leak is somehow tied to the DOJ Montana. This is not 100% sure, but i received multiple indicators that they are closely connected the leak.
There were more attempts to reach official contacts than documented here in the PostMortem. The list only includes those I could pinpoint with a reasonable degree of certainty.
I will not answer questions on how the forensics software works. This is out of scope for me. If you want to keep your phone safe: make it stay in the BFU state most of the time, choose a long and complex PIN, avoid cloud backups and do not install tracking apps.
I do not know if the share was writeable for everyone. This is also out of scope. Therefore I cannot say how difficult it would have been to manipulate an investigation. But my guess would be, that at least for a skilled atacker this would seem quite possible.
Purpose of the PostMortem is to provide an opportunity to learn for the affected party and those in danger of making similar mistakes. Futhermore I feel responsible to give all the people involved some closure.