They argue that the typical serial murderer travels, usually from state to state, in search of victims of rape, torture, and murder. Very few murders are driven by delusions and are not medically or legally ill. Serial murderers are usually psychopaths who lack internal control and have an excessive need to control and dominate others. Serial murderers know right from wrong but simply don't care. Their target usually involved innocent strangers who had certain physical characteristics or who might simply be accessible. The authors study the motivations for mass murders and note the difficulties police officers face in catching them. (Levin and Fox,