Let's hear it for HHJ Patrick Thomas QC.
This type of offender does not think in terms of killing the girl. She is more useful to them alive, they think of the crime as undetected and undedetectable, killing one or two would certainly bring the police in, on a massive scale, and the sentence could be whole life or would be life with a minimum, before being considered for release, of about 30 years,and that to be served in constant danger (from other prisoners) or substantially in isolation.