Edit:
> Most of them are product managers, software developers. … They work with the policy teams with an internal set of tools to forward links and explanations about why they need to be removed.
Yes, all social media have open channels with law enforcement. That's because social media have legal obligations and when someone comes to a moderator claiming to be a law enforcement officer working on a kidnapping or preventing a terrorist attack and needing time-sensitive help to save lives, you don't want the moderator to have to guess whether that's a real emergency or a hoax.
It's... not a secret. If you live in a democracy, you can quickly find out the name of these channels, they have websites.
Source: I've been part of a moderation team. Not on something that large, though.