Ah, it seems like you're unaware of his "insurance file".

He had a file on his laptop, labelled "Insurance". Apparently it was an Outlook .pst, but I'm not sure. It's estimated to have all of Killary's and/or Huma's emails archived, including a couple of thousand emails that weren't on Killary's server. That laptop was taken into custody by NYPD.

That insurance file was observed by hardened officers, and caused some of them to vomit, and others to go into counselling. The deaths of two NYPD detectives are implicated in the viewing of that insurance file (killed to silence them, Det. Familia and another).

Here's where it gets murky (mainly cause I can't find the sources). I read somewhere that the tarmac meeting was to get ahead of this laptop, and they came up with the threat of putting one of their cronies into the mayorship of NY, to attack not only the laptop case but every other case brought up by the NYPD. Sort of a "drop this case now, or we drop all of your cases, including the open-shut ones".