Some of these documents are so highly classified that they are to never leave secure premises. This is absolutely theft; theft of highly classified information.
So, he had to have known what the material contained and he had to have persuaded someone to remove it from the premises. This person needs to be found. In addition, classified materials are guarded. They had to get around that guard too. That person also need to be found.
This is interesting:
All classified material must be stored in a secure room, a GSA-approved storage container, such as a cabinet or safe or a vault or modular vault, or a sensitive compartmented information facility (SCIF).
a.
Confidential material may be stored in a secure room, a cabinet or safe, or a vault or modular vault. Confidential information may also be stored in a SCIF. No additional protection is required to store Confidential material in any of these containers or facilities.
b.
Secret material may also be stored in a secure room, a cabinet or safe, a vault or modular vault, or a
SCIF. However, if Secret material is stored in a secure room, then supplemental controls are required to ensure its protection. We'll look later at the specific supplemental controls required for Secret material.
c.
Top Secret Like the lower levels of classified material, Top Secret material may also be stored in a secure room, a cabinet or safe, a vault or modular vault, or a SCIF. However, regardless of whether it is stored in a secure room, a cabinet or safe, or a vault, Top Secret material always requires supplemental controls. We'll look later at the specific supplemental controls required for Top Secret material.
d.
Sensitive Compartmented Information (SCI) There is only one acceptable place to store SCI, and that is in a SCIF. Although any type of classified material may also be stored in a SCIF, SCI may NOT be stored in anything other than a SCIF.
There's so much more:
https://www.cdse.edu/Portals/124/Documents/student-guides/shorts/IFS0024-guide.pdf