Episode 5.7 "If it Bleeds, it Leads"
Jane to Kirkland: "Do I know you?"

Kirkland (shaking Jane's Hand): "No, But I know you!"...

We now know that Kirkland probably knew Jane since before Jane started consulting for the CBI, since homeland security. 

Jane, however, senses that Kirkland is familiar. He's seen him before but can't put his finger on it. Actually, he's seen his identical twin, who's undergone a change in appearance and changed his name to... Walter Mashburn.