By OLGA R. RODRIGUEZ
SAN FRANCISCO (AP) — Groups of thieves ransacked jewelry and high-end clothing stores throughout the San Francisco Bay Area over the weekend, shocking holiday shoppers and prompting concerns about the busy retail season. The mob attacks are believed to be part of sophisticated criminal networks that recruit mainly young people to steal merchandise then sell it in online marketplaces. Experts and officials say the thefts are happening nationwide and are ratcheting up as the holiday shopping season gets underway. Police promised to step up patrols in retail areas and Gov. Gavin Newsom said the state would provide additional resources to help cities and counties.