Mantell was a WWII top-notch pilot, honoured with the Distinguished Flying Cross and Air Medal for courageous action and heroism respectively. He continued his career in military in Kentucky Air National Guard. Many believe that he was the first person to die while tracking a UFO.
Mantell found the UFO but he never reached it at 25,000 feet as his plane dived towards the ground and crashed. The UFO disappeared after twenty minutes without a trace. It was presumed that Mantell flew beyond his limit and did not have enough oxygen to breathe, as a result, he blacked out and lost control of the plane. However, there was a sensational news by a local newspaper on the next day mentioning that the pilot’s plane was shot down by magnetic rays or in other words he was killed by extra-terrestrials.
Only Mantell could tell what was really happening but unfortunately the truth was buried together with the ace pilot. One thing that can be called as fact is that Mantell was the first person to die while investigating a UFO sighting. He died while chasing the truth.