After completing my dissertation proposal, I got data from a company for the idea. After that, I was searching my dissertation advisor.
I talked with an assistant professor(A), and then he asked me to send all of the collected literature and the proposal to him. A few days later, he informed me that he could not accept me as his student.
I found another professor(B) and then began to work with him(B). However, my new advisor(B) forced me to give up the proposal without any clear reasons. So I needed to give it up because for a month, he(B) kept asking me to find a different topic.
About 2 years later after the time, I found that my advisor(B) and his former student(C) had been working on my proposal topic and began to submit several papers.
The story was that: His former student(C) was in a relationship with the assistant professor(A) I sent my proposal and literature to. The assistant professor(A) sent the stuff to her(C) (my advisor's former student). She(C) contacted my advisor(B) to ask for my advisor's help to develop the idea and so….
Such a thing happened one more time. My advisor's point(B) was that she was unable to find a topic and so he(B) had provided research ideas to her(C), and so on.
This Fall, her(C) tenure will be under review. I'd like to send a letter to her dean to inform this. However, I am unsure how to do that effectively. Any suggestions?
By the way, I do not work with the advisor(B) anymore. I had a chance to talk about this matter with the assistant professor(A). He said that he just shared the proposal with her(C) because it was an interesting idea. He did not know the other stuff - why and how she worked the topic with the professor(B). Finally the advisor(B) said that it happened because she(C) brought the idea to him before I met him.