An illegal alien from Mexico was being held without bail in the murder of 5-year-old Anna Cruz, sheriff’s investigators said. Arturo Miranda, 21, was arrested by deputies when he went to the Whittier-area apartment building, about 18 hours after the child’s widowed mother, Emilia Cruz, told friends she had heard a noise in her living room and saw a man in shorts lying on the kitchen floor with her youngest child. The man fled, but the mother and her son recognized the intruder, who neighbors said had often loitered around the apartment building. Sheriff’s Lt. Barrett Fitzgerald said Miranda evidently “didn’t think he could be identified,” and strolled into an acquaintance’s apartment, where he was arrested. An autopsy found that the child was strangled, the coroner’s office said, adding that tests were being conducted to determine if she had been sexually assaulted.