The arrest of 15 suspects over several weeks in the Bay Area was the culmination of a six-month investigation into the thefts that also netted more than $50,000 in cash, four handguns and an illegal assault rifle, ammunition, evidence of identity theft, tools and more than 1,000 catalytic converters.

Changes in hours and security were being discussed by major retailers across the Bay Area as the looting attacks cast a grim shadow on Thanksgiving shopping for thousands of stores and their customers.

Police are investigating whether the theft is connected to similar thefts at Stanford Shopping Center in Palo Alto. More than $150,000 in handbags were taken from the Neiman Marcus store on May 19 and $100,000 in handbags from the Louis Vuitton store on June 7.