Make the fire just big enough to cause a slow death.
-—fire just big enough: It’s been done before. The book Savage Kingdom well describes how the northeast Indians disposed of killers and rapists in the early 1600’s. Spread eagle them. Build a fire where they could see it. Then start slicing off pieces, tendons first, and throwing them into the fire. Last thing was the scalp, peeled off, back to front, so the last thing the dummy saw was his own face burning. It was important to have another captive, not a tribe member, watch so he could spread the word about the price of being a dumbass.