President Obama was traveling to Aurora, Colo., to visit with families of victims of the shooting as well as local officials, the White House said. Meanwhile, the Aurora police chief said accused theater gunman Jame Holmes was acting alone when he plotted and carried out last week\'s movie massacre, the Aurora, Colo. police chief said Sunday. Chief Daniel Oates denied media reports detectives were seeking a second person of interest in their investigation into the slayings of a dozen people at an Aurora movie theater during a midnight showing of the new Batman film. \"All the evidence we have, every single indicator, is that ... this is all Mr. Holmes\' activity and that he wasn\'t particularly aided by anyone else,\" Oates said on CBS\' \"Face the Nation.\" \"We\'re building a case to show that this was a deliberative process by a very intelligent man who wanted to do this.\" Aurora police and federal agents continued searching the one-time grad student\'s small apartment for evidence. Investigators were able to enter only after a bomb squad cleared the residence of multiple booby traps. Oates said Saturday Holmes had been purchasing ammunition and explosives to booby-trap his apartment for almost four months. \"What we\'re seeing here is evidence of, I think, some calculation and deliberation,\" he told reporters. Holmes, 24, spent Sunday in the Aurora jail awaiting his initial court appearance Monday. Holmes\' alleged motive in the slayings remained unclear. A video has surfaced in which Holmes discusses his interest in a neuroscience phenomenon related to time, ABC News said Sunday. ABC said the video it had obtained was recorded six years ago at a college science camp in his native San Diego and features an 18-year-old Holmes talking about research into \"temporal illusion.\" \"Over the course of the summer I\'ve been working with a temporal illusion,\" Holmes says in the video. \"It\'s an illusion that allows you to change the past.\" Holmes apparently did not get into much detail on temporal illusions, which are related to the perception of time. He did, however, say he had a mentor who was also interested in the topic. \"He also studies subjective experience which is what takes places inside the mind as opposed to the external world,\" he said. \"I\'ve carried on his work in dealing with subjective experience.\"