Death Threat for a Hitman

It's not wise to threaten a hitman.

A gangbanger tries to cash a check, not realizing the man behind the counter has a side gig where he gets paid to kill people.  Sometimes, threats can lead to freebies.

This story first appeared in Fantastic Stories of the Imagination.  Strange place to find a crime story, but there you go.  The story also appears in Quick Shots and The Hitman Stories (an omnibus edition of all 6 hitman stories).