Edgar Wallace 
The Green Ribbon 

In „The Green Ribbon” an insurance investigator researches the accidental death of a jockey. His inquiry leads to an illegal gambling organization, as well as the knowledge that the jockey’s death was not accidental. He also saves the life of another jockey who has been the victim of a couple of accidents. One of Edgar Wallace’s occasional horse racing novels which centers of a betting syndicate involving the jovial Mr. Trigger, the sinister Dr. Blanter, the strange Mr. Goodie, and the slippery disbarred lawyer Rustem. How does the Green Ribbon tipping agency keep on picking winners? Looks like there’s dirty work going on at the race track…