Conversation so far:
When did Robert Mueller start a law career?
1973
What did Robert Mueller do for the firm Pillsbury, Madison and Sutro?
Robert Mueller worked as a litigator at the firm Pillsbury, Madison and Sutro in San Francisco.
What did Robert Mueller do after working as a litigator for Pillsbury, Madison and Sutro?
Robert Mueller then served for 12 years in United States Attorney offices.
What did Rober Mueller do for the US Attorney?
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.

Question: What did he do after San Francisco?
Self-contained rewrite: What did Robert Mueller do after San Francisco?