What did did he say in your exchanges? If you feel inclined to disclose.. im only asking since perhaps it's relevant to the issue at hand.

Otherwise. I agree with another poster here to take what he said at face value. But ithe only way to have 100% confirmation, you can simply ask him yourself. Maybe something like "just curious why you've been liking my photos constantly, it's very unlike you" or you could get straight to the point.