A Santa Barbara Bank & Trust branch in Montecito’s Upper Village was held up late Tuesday afternoon, and the alleged gunman escaped with an undisclosed amount of cash. Authorities are asking for the public’s help in locating the getaway vehicle: a purple BMX-style bicycle.

According to Santa Barbara County sheriff’s Detective Sol Linver, the suspect, described as a white male, entered the bank at 1483 East Valley Road at about 4:25 p.m. He allegedly brandished a small black handgun and demanded cash.

The man — wearing a black motorcycle helmet, gray jacket, gloves and backpack — fled the branch on a purple BMX-style bicycle, Linver said. It is believed that a red dye pack, commonly used by banks to mark stolen money, was detonated inside the backpack.

“If anyone sees a purple BMX bike abandoned or a red dye-stained backpack, please call us,” Linver said.

Six sheriff’s patrol cars, two K-9 units and a Ventura County Sheriff’s Department helicopter responded to Montecito to search for the suspect. For hours afterward, the helicopter was slowly circling above the Upper Village neighborhood.

Detectives urge anyone who sees someone matching the description and possibly covered in red dye to immediately call the Sheriff’s Department at 805.681.4100.

— Noozhawk intern Daniel Langhorne will be a junior at Chapman University in the fall. He can be reached at dlanghorne@noozhawk.com.