Cover stories (6)
I believe the answer is:
alibis
'cover stories' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for alibis that I've seen before include "Legal defences of being somewhere else at times of crimes" , "Defences - was elsewhere at time of crimes" , "They're useful to have if accused of crimes" , "Defences to charges - was elsewhere at the time" , "Proofs accused was elsewhere at time of crime" .)