An unusual necropsy

"Thank God this is the last one" said Dr Lancefield taking off his white robe. He was coming out of the Pathology Department when suddenly he saw four people; One of them was pushing a stretcher. Dr Lancefield glanced at the body covered with a blanket.
"Is this human?" Asked Dr Lancefield while he discovered what sort of men were around him. They all were alike dressing a dark blue uniform.
"We are not sure" answered one of them. "We are officers. We came from the Anthropology Department. Our scientists found out this corpse buried down and we need a professional".
Speechless, Dr Lancefield removed the blanket and observed it. Then, he stared at them, he was concerned. "Is this a joke?"
"Not at all. Look, we have no time. Some of us wanted to destroy it. We`re fleeing. If you´re interested in what or who this was you better start working. You only have 6 hours".
Dr Lancefield took the body into the autopsy room. "God, how could I start?" He took an empty sheet and his dissection instruments. He wrote: "male, age not calculable, 2.6 m height, 130 Kg weight" he stopped writing "It´s useless, how can I describe this sort of daemon with vestiges of wings and tail? The dissection might be more useful" He did all the procedures he knew, he observed tissues with the microscope, he mixed some chemicals and he ran several tests. Finally the men interrupted him.
"Time´s up. They´re coming. Give us what you have so far" the officer yelled.
"Impossible. What we have here, gentlemen, is not a human being. The information must be confidential until I......" violently one officer seized the file from his hand and they all ran away.
"God damned it. I supposed they´d do something similar" Dr Lancefield had shifted the documents; He sank them on formol and he threw them into the fire. "Now no one would ever know their secret".