ccmay has made an excellent point. The question which needs to be asked is: Does the individual just possess the material, or has she used it for terrorist purposes?
If the mere possession of such materials constitutes a terrorist crime, many military and former military members need to destroy their technical and field manual libraries.
Mere possession of a manual might be one thing, but a computer file can be disseminated much faster and easier, I would assume they have a track record of everyone who got a copy and are currently hunting them down. Yes I meant HUNTING in a literal sense.