The move is to stop "grab and run thefts" which have happened at this location.
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Nordstrom asked Walnut Creek for help and will reimburse the city.
Officers will have to volunteer for the assignment.
The city council unanimously approved the deal Tuesday night.
VIDEO: Video shows stream of handbag thieves sprinting out of San Francisco Neiman Marcus
Video shows handbag thieves sprinting out of SF Neiman Marcus