I have a very strong suspicion that a final written exam of a student was written by another student of mine. The style, the wording, even font, etc. are just way too similar to be random.
I am wondering what is the best way to confront them in order for them to feel comfortable to admit it instead of perhaps being defensive and denying it.
Do you have experience in confronting students in what works and what definitely does not work?
--- more context ---
The context is a Data Science class where students have to do a data science paper. Allegedly, one student, who is very good, did the work of another student who is a very beginner.
That very good student for instance wrote their code in a very specific rather advanced way and used a lot of extra libraries that we never discussed in class. When I reviewed both of their programming codes, they were written in the exact same way, with the same variables names and the same odd libraries. The newbie student could never have written this themselves in my opinion. On top of that they are family related.
How much more evidence do you need for your cognitive Bayesian model?