Sounds to me like you were onto him pretty much all along though at least from the time you were questioning about him with your friend..if he hadn't triggered some red flags before that, you wouldn't have questioned her about him.

Just one thing to remember, when red flags start flying....& you start to question....trust your gut feelings & let them be your guide. Why let your emotional self keep going when your logical self is already telling you there is a problem. You caught it....you just didn't trust yourself that you had.

First red flag I would have had was him talking about his missions....missions are classified & CAN'T be talked about whether contractor or not....but it sounds like you are wiser than you give yourself credit for being.