Alfred Hitchcock and the Three Investigators: The Mystery of the Green Ghost by Robert Arthur, 1st Scholastic paperback printing, TX1916, 1971, 181 pages. Illustrated by Harry Kane.
DESCRIPTION:“…in the pages ahead you will meet, as the title of my book suggests, a green ghost. In addition to the ghost you will encounter some strange pearls, and a little dog who plays no part in the story because he does nothing at all. Or does he play a part? Sometimes doing nothing is as important as doing something…” (from the text)