An NSA employee, Procopius of Caesarea, leaked a vast database of scandalous and illegal government programs he had access to as an insider.

Spying on citizens, funding foreign terrorists who attack the homeland, sexual compromise of high-ranking military officers...

https://en.m.wikisource.org/wiki/The_Secret_History/Introduction

( Procopius was subject to an immediate, armed and hysterical official reaction, but was already beyond the government's reach, and his work is still in print.)