They are probably doing some mining. To understand how that works.
They have already purchased cryptocurrency and I'm sure they are continuing to do so here and there to understand it better.
And to try to ensnare people they think are commiting crimes like laundering money.
Exhibit A:
Me: “How'd it go with [Friend #1 I introduced to Friend #2]?”
Friend #2: “Dude, your friend introduced me an FBI agent without telling me and I sold him Bitcoin. WTF?!”
Me: (thinking during awkward pause)
Me: “Oh, sorry about that. How'd you know he was FBI?”
Friend #2 (hands me the FBI agent’s card and says): “Because he gave me his card after I sold him Bitcoin! F#@$!”
Me: (thinking during awkward pause)
Me: Friend #1 should have told you in advance. But he’s a nerd and a total straight shooter. He means no harm.
Friend #2: …
Me (hastily): “And I'm sure it's fine.”
Friend #2: “How is it fine?”
Me: (Thinking during awkward pause. Tries to remember how I get out of these types of situations when my spouse asks me the same thing.)
Me (finally): “Because you didn't do anything wrong. The agent probably just wanted to learn how it works.”
Friend #2: “Dude, the fucking FBI!”
Me: (thinking harder during another awkward pause)
Me: “I understand it's scary. But it can be a good thing. Friend #1 has the FBI as a customer. Maybe because Friend #1 introduced you to the FBI agent, you are more likely to be perceived as legit by law enforcement.”
Friend #2: …
Me: “How about them Warriors?”
Friend #2: …
Me: “Durant!”
Friend #2: …
Above reconstructed from memory and exaggerated for dramatic effect.
I Also heard that the biggest wallet on bitcoin belongs to FBI.