The neighbor says, as she understood it, the suspect had lived in the apartment with his girlfriend until their recent break-up. The suspect had then moved into another apartment nearby two weeks ago. She says he had returned to the old apartment and was banging on the door of his old apartment, demanding to be let in. The neighbor also said she believed the suspect had a 9-11 tattoo.Of course, Sikhs had nothing to do with 9/11, though people sometimes mistake Sikhs for Muslims (and mistake Muslims generally for the subgroup of Muslims behind 9/11), but in a planned killing where someone goes to the place of worship, it would be harder to make the mistake.
ADDED: The FBI special agent in charge of the investigation said: "We are looking at ties to white supremacist groups."