As was mentioned in the other comment, it is easy to miss a dialogue by accident. And if the person have nothing new to share, it just repeats the answer to the last question, so you need to click through that.
It would be nice to have the option to remove a connection on the murder board, especially one I made by accident since I did not know how to make the connection and I was randomly clicking to figure it out.
It seems like a nice instance of the murder-mystery genre, but as I usually do not play games like this I cannot really judge it.