The FBI investigation is providing ammunition to opponents of John Conyers, who has been married to the former Monica Ann Esters for nearly 20 years and who has served in Congress since 1965.

U.S. Rep. John Conyers, (D-MI), speaks at a town hall meeting for Congressman Keith Ellison at the Church of the New Covenant-Baptist on December 22, 2016 in Detroit, Michigan.

In this May 24, 2016, photo, Rep. John Conyers, D-Mich., ranking member on the House Judiciary Committee, speaks on Capitol Hill in Washington during a hearing.

Conyers also had scandals of his own. In 2009, his wife Monica Conyers, a Detroit city councilwoman largely elected on the strength of her husband's last name, pleaded guilty to bribery.

City Council member Monica Conyers, the wife of a prominent congressman, sought political support from Baptist pastors and prayers from constituents Tuesday as her re-election bid collided with a ...