Albert Einstein suggested a scientific basis for the reality of ghosts; if energy cannot be created or destroyed but only change form, what happens to our body's energy when we die? Could that somehow be manifested as a ghost?
It seems like a reasonable assumption — unless you understand basic physics. The answer is very simple, and not at all mysterious. After a person dies, the energy in his or her body goes where all organisms' energy goes after death: into the environment. The energy is released in the form of heat, and transferred into the animals that eat us (i.e., wild animals if we are left unburied, or worms and bacteria if we are interred), and the plants that absorb us. There is no bodily "energy" that survives death to be detected with popular ghost-hunting devices.