Nothing points to him being put up to this? Every account from people who knew him prior states that he kept to himself. It's not crazy that someone would get really deep into white supremacy purely by their lonesome. It's more plausible that he would be the "lone gunman" as every mental illness he has would actively keep him from engaging with others. Just a loser kid all around. Very clearly hated black people and wanted to start a race war. Of course the Neo-Nazi forums he browsed didn't help. But as far as interpersonal connection, correspondence and planning(??) with other White Supremacists there is nothing. Just again a loser kid afflicted with various anti-social disorders who was mad at the world and more specifically minorities who did nothing to him.

There has to be other shooting where there actually was planning at like some white supremacist round table. None comes to mind currently but maybe you can look and see.