Citing how rising crime in Ireland and South Africa has benefited the crime fiction scenes in those countries, Peter asks, "Does real-life crime influence crime writers? In what ways?"
I'd say crime inspires writers as anything else can. Crime writers specifically are, of course, inspired by crime--or, to broaden things, what they see as crime.
Every locale has a different flavor of crime. To paraphrase Bruen's comment, one can't write about crime in a particular place until one knows the nuances of a crime there.
To Roger Smith's point, writers are called to reflect their times to an extent. Now that crime is more prevalent in South Africa, he's writing about it.
While I don't wish crime on anyone, at the most basic level, one can't imagine how it feels to be wronged, how it feels to want revenge, until one has been wronged or closely observed others wronged.
Keen eyes will note my allusion to The Lineup's basic guideline: We want poets' honest, powerful reactions to what they see as crime. Gratuitous anything is discouraged.