"The Walnut Creek Police Department is actively monitoring intelligence that indicates the group of thieves who stole from the Broadway Plaza Nordstrom last night are considering similar activity later today," police said on Twitter on Sunday.
Earlier on Sunday, the Walnut Creek police said that they were investigating an organized theft at the Nordstrom store.
"Three people are under arrest today following an organized theft at the Broadway Plaza Nordstrom in Walnut Creek last night," the police said, explaining that they received 911 calls on Saturday when "approximately 80 people entered the store and immediately began stealing merchandise."
According to police, two Nordstrom employees were assaulted and one was pepper sprayed. One of the three people arrested had a firearm.
"The remaining participants in this criminal mob fled from the area in cars at high speeds," police said.
According to local media reports, about 25 cars blocked the street on Saturday night and looters rushed into the Nordstrom store in Walnut Creek, later getting back into their cars and fleeing with goods.