Investigators looking into the motivations of two men accused of killing three people at a San Diego mosque Monday are trying to authenticate a document posted online that purportedly details their motivations, three senior law enforcement officials said.Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content.The 75-page document has sections apparently written by Caleb Vazquez, 18, and Cain Clark, 17, the suspects identified by law enforcement officials briefed on the investigation. The writings are filled with extremist material espousing anti-Islamic, antisemitic and anti-LGBTQ views. The authors refer to accelerationism, a white supremacist ideology that...