This person was dead for over a week before being found. Notice how the skin is blackened. A great deal of liquid blood has poured from the lungs. This is the result of decomposition and appears on about the fourth day.
This "bloody purge" probably gave rise to superstitions about vampires. About the fourth day post-mortem, the blood becomes liquified and gas builds up in the body due to bacterial decomposition. So in ancient times, when someone had died who was presumed to be a vampire, they would excavate the body and drive a wooden stake through the chest. Due to the gas produced by the decomposition and liquifaction of the blood, the body would spurt out blood and gasses would be released, sounding like a sigh.