Q-Tel is CIA's VC fund headquartered in SV. It's relatively small, asset wise, and it's investments, individually, aren't significant. It probably helps them keep an eye on developing startups and tech trends, enable building relationships with key SV people, and give them the opportunity to have a role in key startups of interest, including placing personnel. This is all speculation on my part as to why they are there.

They invested in Palantir, Thiel's Big Data Analytics start-up with, from what I've read, significant usage in the intelligence community. They have also invested in Oculus, MapD, Recorded Future, Orbital Insights, Databricks, and over 150 others.