Note:

• A non-speculative mystery story. It is in this database due to appearing in the anthology Tricks and Treats (1976), which is indexed by Contento1.
• Contento gives a first publication date of 1965, no venue specified.

Synopsis: A police detective is talking to a suspect in the murder of a blackmailer. He says that they should be able to identify the killer because of a handprint he left and an unusual glove. The suspect then has to admit that he is the man, revealing that he has six fingers (a real-life condition that occurs in approximately one out of 3,000 births).