Yes, it is. Many movies or books titled 'Night of the 12th' are often based on real events. These true stories usually add an air of authenticity and intrigue to the narrative. They can draw in audiences who are interested in real - life mysteries or dramas.
It could be about a crime that occurred on the night of the 12th. Maybe a murder or a significant event that took place during that night which was then turned into a story based on real - life happenings.
I don't know for certain. It could be based on some truth or could be the author's imagination. You'd have to research more or ask the author to know for sure.