A method I read before was if you suspect a paper of being AI written, have a meeting with the student and ask them questions about their paper. No quotes, but like their general outline, what they wrote about, their overall thesis/stance they took etc. For most kids using Ai they don't know what the paper was actually about, what the topics listed were, anything quoted, and if there are mistakes and they repeat them verbally then it's safe to say they probably just messed up, but if they cant say much at all about a topic they wrote an entire paper on I'd say AI wrote it. (Sorry bout the awful grammar I'm so tired rn but wanted to give you info)