Criminologists have emphasised the importance of ‘opportunity structures’ as a means of ascertaining the increased likelihood of criminal behaviour in certain contexts – noting that crime is more likely to occur when there is a combination of a possible victim accessible to predation, a motivated offender, and a lack of competent guardians. That the victims of serial killers tend to be drawn from modernity's disposable classes can also mean that these victims are outside of effective systems of guardianship, and are targeted not only because they are more accessible, but also because their deaths are less likely to generate timely investigation or legal consequences.