I am forced to write this question as I believe it is unethical and needs to be addressed in my faculty. I suspect a faculty member in my university has the habit of writing his master's degree students' thesis (for free or for a fee). I believe he does that for a fee. A colleague has mentioned this before but that colleague isn't a board member so I can't really take his word officially. I noticed that for several thesis I examined for the examination board, his students have very solid thesis but would have you questioning their abilities during oral presentations. Some colleagues think it's stage fright but I believe it is more than that. This faculty member always requests that corrections for the thesis be mailed to him to "pass to his student". I think he's just doing the corrections and submitting final copy. This faculty member taught me in my undergraduate years in the same faculty and I heard some stories of his shady dealings with students then.
Question: How can something like this be investigated since there are no mechanism in place to limit what a supervisor contributes to his students' thesis? It is difficult to get the students to testify as this is what most of them would want by default.