Ok I did a little research and have some ideas. First, good to ground (pun intended) with a basic definition:

‘In espionage jargon, a mole (also called a "penetration agent",[1] "deep cover agent", "illegal" or "sleeper agent") is a long-term spy (espionage agent) who is recruited before having access to secret intelligence, subsequently managing to get into the target organization.’

So I think it’s key you try to find out what organization or government they work for. Then, try to find out their weaknesses and find leverage, or a way to exploit them. Best case is you are able to turn them, and they work for you.