Four departed last Oct/Nov. Can't remember exact details.
https://www.cnbc.com/2018/08/31/two-prosecutors-leave-mueller-team-including-cyber-expert.html
Ryan Dickey and Brian Richardson appear to have left the team this summer, according to a report by CNN, which first broke the news of the departures. Mueller's team now has 15 attorneys.
https://edition.cnn.com/2018/10/02/politics/mueller-two-prosecutors-leave/
Washington (CNN)Kyle Freeny and Brandon Van Grack, two prosecutors who worked on Paul Manafort's criminal cases, are ending their tenure working for special counsel Robert Mueller.
Just Watch!