Woman Arrested for Allegedly Stabbing 12-Year-Old Boy During Robbery at San Leandro Bank (NBC)

A 12-year-old boy was stabbed by a woman during a robbery at a bank in San Leandro on Monday, police said.

The boy, who didn't know the suspect, was transported to a hospital and will require surgery, San Leandro police Lt. Robert McManus said. The boy is expected to survive his injuries, McManus said.

"He was stabbed from behind while he was seated in the lounge chair," McManus.

At about 11:30 a.m., the boy was waiting for a family member to finish an appointment inside the Wells Fargo bank when a 32-year-old woman stabbed him in the back three times, police said.

"He thought he'd been punched in the back," McManus said. "Being punched in the back was actually the knife entering his body."

Authorities said the boy is from out of state and had just arrived in town this past weekend to visit family.

"I can only imaging what this boy is going through, the shock, the scare," McManus said. "He's probably frightened right now."

Witnesses said the suspect, identified as Oakland-resident Iyona Hammond also robbed another person making a cash deposit.

Security guards were able to contain the woman for a short time before she rushed out and right into the hands of the police.

"In cases like this the first thing that would come to mind is that is she mentally stable," McManus said. "That we don't know right now."