The Whistler - Meet Mr. Death

Jerry Mason, a drug store clerk, embezzled eighteen hundred dollars from his employer.  He gave the money to Herman Arnold, a gambler who told Jerry he had a fool-proof scheme for doubling the money.  Unfortunately, Herman was killed that night and the money disappeared.  Jerry is now afraid of losing his job and going to jail.  The next night, as he is closing the pharmacy, a stranger approaches him wanting to purchase some aspirin.  He pays for them with a one thousand dollar bill, and tells Jerry to keep the change.  The stranger also told him there were four more one thousand dollar bills for him.  He just needed to "accidentally" increase the dosage of Chloral Hydrate for one of his customers.