Open this photo in gallery: A memorial to those killed stands at an entrance to the Allen Premium Outlets mall after the mass shooting occurred in Allen, Texas, on May 8.Joe Raedle/Getty Images Federal officials are looking into whether the gunman who killed eight people at a Dallas-area mall expressed an interest in white supremacist ideology as they work to discern a motive for the attack, a law enforcement official told The Associated Press. The official cautioned that the investigation is in its early stages. Federal agents have been reviewing social media accounts they believe were used by Mauricio Garcia,...