I can't see the prosecutor not using this, especially because she for sure would have had his skin cells under her nails. I don't think he could have gotten rid of all traces, and left blue paint fragments under her nails.
It may not even be worth our time to speculate over it..but I wish we could have been given a straight answer as to why it wasn't used.
Do you think the fingernails could have had the dna cleaned out prior to the paint chips?
Rapists have tried to get rid of evidence by forcing the victim to take as shower...would all the trace evidence/his dna be cleared from her nails if he forced her to use a nail brush under water? Just some thoughts to ponder..