A woman was arrested Monday on murder and arson charges after a fire swept through a three-story apartment building in suburban Denver, killing a 5-year-old boy and displacing more than 30 people. Investigators believe Alondra Michel, 37, was involved in a domestic violence incident with a resident on the main level of the apartment building early Monday morning and intentionally set something on fire, according to Aurora police. The blaze quickly spread to other apartments, including the second-story unit where the boy was found.