Dan McCrum had been on the Financial Times’ financial fraud beat for a while, but nothing prepared him for the Wirecard investigation. “At one point, we realise there’s this team of 30 private detectives running around London with cameras, trying to find evidence of short-sellers, collusion, journalists talking to short-sellers – that sort of thing.  “And we flip one of them. My boss goes to talk to him. And he’s this ex-copper, who turns out to be a bit of a nasty character. And he starts saying things. He’s like, ‘Oh, yeah, we track journalists all the time.’ And he…