There was definitely some history there that John had no clue about but he had no doubt that his curiosity would get the better of him in time and he'd attempt to find out as much as possible. For now, though, he had work to do.
He knew this was a risk - Enzo had threatened him once already since he arrived and John didn't doubt he'd act if he felt Bonnie was in danger. Still, they wanted to know if she was a witch and this was the best way he knew how. "Sorry, luv," he told the girl as she looked down at the blood, "before Hopkins went barking mad and started seeing witches behind every doorway he found this little gem," he said as he wiped the blade with a sterilizing wipe before tossing it back into his bag. "You didn't feel the blade, which means that whatever happened to you, Bonnie, you're still a witch. Now, why you can't access your magic is another matter entirely," John snapped his bag shut and looked at Enzo, "I'll see if I can cobble together some spell or other to help with that, but without my library I'm not sure how much use I'd be. Now," he said heading for the door, "if you'll excuse me I have a date with a hot red-head and I'd rather not be late, if it's all the same," he said with a smirk. "Nice to meet you both."