Microsoft co-founder Bill Gates told a U.S. House of Representatives panel investigating the late financier Jeffrey Epstein that his meetings with the convicted sex offender were “a grave error in judgment.”

The appearance of Gates, one of the world’s richest men and the face of the technological revolution for a generation of Americans, was a striking testament to the broad and influential network of connections Epstein cultivated. Epstein died in a New York jail cell in 2019 while awaiting trial on federal sex-trafficking charges.

The release of Justice Department files on Epstein forced by an act of Congress has spurred close public scrutiny of Epstein’s past associations with powerful figures, including Britain’s ex-Prince Andrew, former Harvard University President Larry Summers, U.S. President Donald Trump, former U.S. President Bill Clinton and Apollo Global Management co-founder Leon Black. Those men and Gates have denied any wrongdoing.