104-106 Novel: The boy who invented the bubble gun

The main character is Julian, he drew a picture of the bubble gun. And he wanted to creat it became a real gun, but he did not have money. And the other characters are Marshal and Colonel. Marshal always helped him when Julian was accused as a killer. And Colonel brought him to government to creat that he wanted. I was not understood with the police who blamed him, as I think the picture is not enough to be used as a proof.