Commentary It was the weekend of the allegedly “random” murders of helpless, law-abiding women by violent homeless men with criminal records and histories of mental illness who had somehow been given the freedom to roam city streets. First came the lethal assault on Sandra Shells, a 70-year-old nurse who had worked at the Los Angeles County–University of Southern California Medical Center for 38 years. As she waited at a bus stop in downtown Los Angeles shortly after 5 a.m. on Jan. 13 for the transportation that would take her to her morning shift, a 48-year-old homeless man, Kerry Bell, allegedly appeared out of nowhere and punched her in the face, causing her to fall and crack her skull against the pavement. She died of her injuries three days later, on Sunday, Jan. 16. According to Los Angeles police, Bell has a lengthy criminal arrest record in several states, including in …