The incident unfolded just before 9:30 a.m. Saturday when a woman walked into the Bank of America branch in the 500 block of South Jackson Street.
She passed a note to a teller implying she had a gun and threatened to kill bank employees if they didn't comply with her demands for cash, said Detective Jeff Kappel of the Seattle police.
The woman fled the bank with an undetermined amount of money but was caught about two hours later south of downtown after an intensive search by patrol officers.
The suspect was interviewed by robbery detectives and booked into the King County Jail for investigation of robbery, Kappel said.
The investigation continues.