First appearing in Blue Bolt # 1 in 1940, and running non-stop until # 95 in 1951, Sergeant Spook was an unnamed police sergeant who made the mistake of leaving a lit pipe near some chemicals and was killed in the explosion.
For no given reason he came back to continue the fight against crime as the second comic book character to return from the dead, following DC’s Spectre by only 4 months.
Sergeant Spook however had no powers other than being invisible and being able to pass through walls while still being able to make contact with solid objects when he chose to, usually he chose to do this by bashing the bad guys on the chin.
It was not long before he teamed up with Jerry (no last name), the only person in the world who could see him, together they took down various gangs of common crooks.
Eventually Sergeant Spook discovered the whereabouts of Ghost Town and went up against the ghosts of famous villains from the past such as Jessie James and Blackbeard who also still interacted with the world, but in a less wholesome way than the Sergeant.