I found a dead animal in a bag at work. Should I be worried?

That would be upsetting to come across, but the possibility of a ritual does not by itself mean anyone is in danger. You can’t reliably tell why an animal died just from how the remains look. Let animal control or the appropriate local authorities handle any further assessment.

From the work-safety side, I’d avoid touching or moving the remains any further, tell your supervisor what happened, and follow the guidance from animal control. If anyone handled the contents, wash exposed skin well and ask a medical professional what to do if there was a cut or contact with fluids.

Try to keep the conversation grounded in what’s actually known: an animal was found dead, and animal control offered a possible explanation. You don’t have to settle the motive yourselves. If the incident is bothering you, it’s reasonable to ask your supervisor for support and let the relevant authorities take it from here.