Legal and moral responsibility lies upon Gage County. That is normally how this sort of thing works. McClennan County in Texas is in a comparable world of hurt from the hundred plus Waco mass false arrests and prosecutions arising from the Twin Peaks biker shootout.
Some years ago, the City of Houston in Texas paid a staggering amount for the mass false arrests of most of the evening customers of a Walmart, and ALL of the customers at White Castle burger place, when an idiot police captain decided to arrest everyone in the vicinity of a purported illegal street racing event. Which included everyone in the parking lot a nearby shopping center.
I’d still argue to throw it on the state’s plate. I’d argue that a County is a subsidiary of The State and The State is responsible for oversight and review of any major convictions won by any elected or appointed prosecutor in its subsidiary counties. And The State is wimping out and abdicating its authority by not actively exercising oversight and sharing responsibility. Otherwise, why even have a state - just have a bunch of autonomous counties who will refuse to prosecute any crime because of the hazards of a forensic breakthrough that hasn’t been invented yet (like DNA 30 years ago).