A man kidnapped a Las Vegas mother while she was walking home from the grocery store and sexually assaulted her for hours inside his work van, according to police. Martin Guerra , who last week was charged with first-degree kidnapping, battery and sexual assault, is accused of exposing himself outside a Smith’s in the southwest valley, approaching a woman who walked by and then throwing her into the back of his van, where he beat and raped her. In a Friday press release, the Metropolitan Police Department said Guerra may have additional victims and urged the public to come forward with any additional information. The attack happened around 11:30 p.m. on April 24 and lasted through the early morning of April 25, according to an arrest report for Guerra, 39. The woman, a mother of two, scratched at Guerra’s face and eyes, Metro said. Guerra punched the woman in the face multiple times, causing her to lose consciousness, police said.…