Pulp Tales Presents #19: The Green Ghost Detective:

As G. T. Fleming-Roberts and numerous other pen names, he wrote mostly stories in the mystery field and was the lead writer on many series including "The Black Hood", "Captain Zero", "Dan Fowler", and "The Green Ghost". This book contains 4 Green Ghost stories from Thrilling Mystery pulp magazine. CONTENTS:
The Case of the Murderous Mermaid
The Case of the Astral Assassin
Case of the Bachelor's Bones
The Case of the Broken Broom