How will I find out if he is gay without exposing myself?

Long story short (though I encourage you to read it, it's kind of funny the mood I was in when I was writting it), I had a weird experience nine months ago. I was walking in the hallway with my friend and I noticed that a guy was looking at me (more like staring). It was obvious he was doing it on purpose, and that he wanted me to realise that, but I couldn't tell whether he was hitting on me, or whether he was claiming my friend. It was still hot, so my friend was wearing a pair of mini-shorts, and she has some pretty nice legs I must admit. I had a huge crush on him before the incident and it got even bigger after it, but I never managed to find him. Since then, I have only seen him four times and completely by chance.

So, after nine months, I managed to track him down. I know name, facebook account, where I can find him, and I think it's time I made my move. I want to find out if he is gay or not, without getting myself exposed. So I told that to a friend and she told me she will use her fake facebook account to talk to him and find out. The thing is, he is very picky on facebook. He doesn't accept friend requests, he "censors" his own timeline when his friends post silly things, in general he is hard to reach if he doesn't know who you are. Therefore, my friend's suggestion may not be the best solution, but it's the only safe means I have to get to him.

I want to proceed with this plan, but I don't know what to write to him. I would like to find out if he is gay. How will I draw his attention so that he answers me, and how will I ask if he is gay without making him freak out? I mean, I would freak out if a stranger knew I was gay. Should I ask him straightforward what he was trying to achieve back then, when he was starring at "my friend"?

Or even better, do you have any other suggestions? As I have no access to most of his stuff on facebook, I can't collect more information on him, so I think I have no option but to talk to him. I would first send my friend to talk to him and investigate. Then again, although I know where to find him, I don't know when, and there is no way to find that out. Unless I start asking people, but I don't want to do that because it will raise suspicion.

PS:
If you read the whole story, I should inform you that I have a bunch of friends at university I have come out to.

 

Ahahahahaha! I just heard it on youtube! Boy that was hillarious!

But this conversation suits better when the other one is a friend. The guy we are talking about is a complete stranger. I first need to get his attention, start talking to him, have something to talk about, and after a week or two bring up the subject the way you describe. It's a good idea, I like corny stuff, I would use it in another case, but I don't think it's suitable now.