It's even more simple than that. You need not have even done anything, simply having it is illegal. Of course, she established the circumstance which caused this information to be stored outside of a secure environment so she is culpable.
Our security department run according to NISPOM and directions out of DSS tells our uncleared employees that if they happen upon something clearly marked ‘classified’ of one level or another to “safeguard it while reporting it to the security department.”
Innocently coming by marked classified material isn’t a crime; keeping and not reporting it is.
Regardless of all these points, she never came by any of it innocently.