Bufo & Spallanzani.

Ivan Canabrava is a writer, turned insurance ivestigator who investigates mysterious deaths involving Bufo Marinus. Bufo Marinus is a frog poison causing catalepsy in humans, simulating death, enabling grand insurance fraud and other crimes. Ten years later, now as a successful writer, similar characters possibly using Bufo Marinus reappear and create an intricate plot full of surprises.