Put it on social media, send it to local news, and let them know what happened. All 4 of our channels have “problem solver” segments designed to shame people who do things like this when law enforcement won’t step up. Seriously, you might get results. Nothing ticks off the public faster than suffering and those bees clearly suffered. I second this. Even if you can’t afford to keep bees anymore, you spread awareness. I wouldn’t call 44 hives a “hobby” lol. I don’t know any thing about the laws, but seeing is largely meant to recover funds. Maybe you could recover at least some.
I would still collect samples and date it if I was you. It’s a shame your state department of ag wouldn’t test them. I am shocked by that. They usually will. Nonetheless, having samples in the freezer could build a case if you get hit again. Emailing the EPA is free and they might want to test them too. You could always pay for testing, look up the USDA AMS NSL in Gastonia, NC. For about $350 they can screen for 200 pesticides. If you have a suspicion of which pesticides are culprits they can do a more targeted screening for cheaper.