You might be thinking of the password vs fingerprint phone unlock. Courts decided that while your fingerprint could be compelled, you couldn’t be compelled to reveal your password as that was private knowledge. That isn’t due to copyright though, it’s a 5th Amendment issue here in the US (The Fifth Amendment grants anyone in the U.S. the right to remain silent, which includes the right to not turn over information that could incriminate them in a crime. These days, those protections extend to the passcodes that only a device owner knows).
She isn’t, but you’re right the others involved were. The trial itself didn’t exactly paint them in a great light. The lead investigator texted that he was going through her phone looking for nudes, the security footage from Canton PD somehow happened to become mirror imaged yet weirdly the timestamps weren’t, the entire investigation itself was an absolute shit show (red solo cups are totally fine for blood evidence, right?) the homeowner (cop) got rid of his dog, destroyed his phone, refloored his basement (possible crime scene), sold the house for $50k under value, and according to him “butt dialed” a potential co-conspirator during sex with his wife at 2am while a dead man was on his lawn. Said butt dialed was “butt answered” according to the ATF agent he was calling who then butt hung up before butt dialing him back.