FIR against government body.

Respected Lawyers I have found corrupt / criminal practice by government employees of municipal body, via RTI , First appeal. Its found current officers are just trying to hide it but actual corruption / happened 40 years back. I m not able to trace the name of officers who actually did it. Or there might be multiple officers or departments involved. But the criminal act / corruption is confirmed. Can i file FIR against municipal body ? I need police support.