1. LDS members can be obligated to provide each other jobs where possible.
2. LDS members (especially of the same congregation) are obligated to not report on each other to non LDS authorities.
And these factors made it sort of an invasion, where after a couple of likely competent LDS members started to make towards the top of government hierarchies, they started ballooning these organisations with their compatriots. Theres been a heap of money spent changing the public perception of this towards "Oh actually Mormons make great public sector employees because they dont drink".
You wont find much for this outside of books usually from retired spooks or journalists who involve themselves in that area.
But the issues have occasionally spilled over to public notice.
https://www.upi.com/Archives/1985/10/02/Former-FBI-agent-tes...