In a style typical of today’s very online internet culture, some of Tyler Robinson’s coded messages were inside jokes meant for himself and his roommate.

© Loren Elliott for The New York Times

Tyler Robinson, the man accused of shooting Charlie Kirk, was a stellar student in high school, raised in a Republican home in Southwest Utah and training to be an electrician.

© Kim Raff for The New York Times

With his right-wing group Turning Point USA, Mr. Kirk engaged controversial topics. Some students were inspired. Others found his views appalling.

© Veasey Conway for The New York Times

The long, strange story of masking and law enforcement.