What we learned watching Robert Mueller for 18 months

Editor's Note: When special counsel Robert Mueller was appointed to investigate Russian meddling in the US election, CNN, like most news organizations, endeavored to learn what we could about the famously secretive team's work. So, in addition to other newsgathering efforts, CNN had journalists who stood outside their offices. Journalists often call this a stakeout. Here, the CNN team lays out the backstory of their assignment and how this investment of time yielded big journalistic returns.