You're kidding, right? The spy is nothing *but* a game of psychology. Sure you can act like an enemy team member, but when humans constantly run spy checks on everyone (be it looking out for suspicious behavior or just shooting anyone who runs by), a spy incapable of understanding these... checks... would be outed in a second.
From a research standpoint, recreating a remotely interesting spy is technology that doesn't exist. We don't have the algorithms. We don't have any mathematical models that can organically represent human psychology. It's one thing for bots to recreate combat. It's not just an entirely new ballgame for AI to understand human psychology, but it's practically a non-existent one. What you're asking for is the stuff of science-fiction.
Come to think about it, AI just smart enough to tell if you are a spy or not based on your behavior is already pretty impressive work. It'd be worth at least a dissertation or two.
And oh, unless I've missed something, Valve's AI is traditionally top notch. Half-Life pretty much introduced enemies that wouldn't blindly run around corners but flush you out with a grenade while flanking you. HL2's human enemies were both interesting and capable of putting up a tough fight. CS's bots aren't half bad, either.