Conversation so far:
Where did Robert Mueller go to school?
Robert Mueller studied at Princeton University, New York University, and University of Virginia
Where did Robert Mueller work at?
After receiving his Juris Doctor in 1973 from the University of Virginia School of Law, Robert Mueller worked as a litigator at the firm Pillsbury, Madison and Sutro
What did Robert Mueller do next for work?
Robert Mueller then served for 12 years in United States Attorney offices.
What office did Robert Mueller work at?
Robert Mueller first worked in the office of the U.S. Attorney for the Northern District of California in San Francisco, where he rose to be chief of the criminal division
Where did Robert Mueller go next after  heworked in the office of the U.S. Attorney for the Northern District of California in San Francisco, where he rose to be chief of the criminal division?
Robert Mueller moved to Boston to work in the office of the U.S. Attorney for Massachusetts as an Assistant United States Attorney

Question: What type of work did he do as an attorney?
Self-contained rewrite: What type of work did Robert Mueller do as an Attorney for the Northern District of California in San Francisco?