According to experts who monitor the radical right, the white supremacist ideology that police say drove the Buffalo gunman has begun moving from the extremes into the mainstream. This is the fifth episode of a five-part series produced in collaboration with The WNET Group’s reporting initiative Exploring Hate.

Violent attacks involving extremist ideology, like the Buffalo rampage, began to rise in the last decade, but officials were slow to recognize homegrown threats. This is the fourth episode of a five-part series produced in collaboration with The WNET Group’s reporting initiative Exploring Hate.

In the years before Barack Obama was elected, many groups on the extreme right kept a relatively low profile. With the election of a Black president, that changed. This is the third episode of a five-part series produced in collaboration with The WNET Group’s reporting initiative Exploring Hate.

Anti-government propaganda, military deployment and the F.B.I. raid in Waco, Texas, radicalized Timothy McVeigh and led to the Oklahoma City attack. This is the second episode of a five-part series produced in collaboration with The WNET Group’s reporting initiative Exploring Hate.