What is the recipe for a serial killer?

There is no single or simple explanation for why someone becomes a serial killer. The causes of such extreme and rare violence are complex and multifactorial, involving a combination of biological, psychological, and social factors. It is often a culmination of various genetic predispositions, mental health issues, personal experiences, traumatic events, social influences, and cultural contexts. Therefore, attributing all instances of serial killing to a straightforward "recipe" would be an oversimplification of a serious subject matter.