The robbery was reported at about 12:20 p.m. Saturday at the Bank of America in the 19000 block of Stevens Creek Boulevard, said Sgt. Rick Sung. The three male suspects were armed, took an undisclosed amount of cash and fled on foot, Sung said.
Police established a perimeter in the area of De Anza Boulevard and Prospect Road near the Cupertino-Saratoga border and notified residents they were searching for bank robbers, Sung said. No buildings in the area were locked down during the search, he said.
K-9 units from police departments in Sunnyvale and San Jose were called in to assist deputies. A California Highway Patrol helicopter was also brought in, Sung said.
The search of the neighborhood ended at 11:45 p.m. with the suspects still outstanding. The sheriff's office is continuing to investigate, Sung said.
"Breaking down the perimeter does not mean we're not going to go after these guys," he said.