Hard to read shy guy? Interested?

I work with a guy who appears to be shy. We work in different departments. Both myself and another coworker have noticed a couple things. - he always appears to be looking at me, when I am not looking. - when we were at a staff training, my friend across the room, noticed he continued to sneak periodic glances at me. - he has approached me to talk about work stuff after his shift was over (he's done with work before me). - when I talk to him, he maintains eye contact. - if I catch him looking at me, his gaze does not wander. - my coworker noticed that one day when I was out of the office, my crush, looked at my office door and appeared sad. - Another time, my coworker observed that he walked past my office and made it very obvious that he was looking in my office. He does appear shy, but I don't know if he is interested. I am also not sure of how to approach it because I am shy when it comes to relationships too.
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+1 y
I should add, he is a single dad of a 4 year old.
Hard to read shy guy? Interested?
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