United States Postal Service Inspector General
According to Wikipedia, David C. Williams was the vice chairman of the Board of Governors of the United States Postal Service from September 13, 2018, to April 30, 2020, and served as Inspector General for the U.S. Postal Service, in the United States Postal Service Office of Inspector General, from 2003 to 2016.
David C. Williams is affiliated with the following schools: