What would make a guy to avoid me if he likes me?

We texted a lot last year, he hinted me that he had had a crush on me, he was very initiative that time as well. There was a reason outside of me what I could not respond to him.
I could feel that he was a bit sneaky about his interest, he was sending random pics of me that his friends took in class (i think he knew someone from my class and he got pics of me from them, but he has not told me who the person was).
Since I made sure I could not respond the same way, our talks decreased. He randomly replies to my stories once a month but sees all my Instagram stories.
We met randomly yesterday, in a queue for a celebrity autograph, i accidently caught him staring to my direction from afar but not on me, I noticed and said hi in a crowd which he responded with another hi. I saw him glancing at me a lot with little gazes, but looked away immediately.
When we were about to get closer in a crowd, i thought of talking to him a bit but he was gone. He texted me that he had left without having an autograph and meeting the person, it was weird because we were there for 2 hours and he left right before we were about to get closer. Do you think he did it porposefully? What would make him to avoid meeting me face to face so brutally? But he texts me like we were very close still but I feel there's something in him that does not let me to approach him with my friendly attitude.