The boy had a terrible expression after hearing out Luke's words and didn't know when he started taking back steps subconsciously. The fact that how he acknowledged Luke in a moment that deeply confirmed Luke's suspension more. The deep scar over his left eye was renowned across the world giving the audience a smooth chance of acknowledging him fast.
Of course, the boy could be one of them but he got scared out of his wits after finding Luke unexpectedly more. The guilt was written all over his expression as he regretted himself for not listening the others a little. He had been warned several times that this book belonged to the untouchable property of underworld. If their Vampwolf found out that the books had gone missing, he would definitely find a way to take back his assets no matter what.
