SAN FRANCISCO -- A San Francisco police officer has been arrested and charged with bank robbery, according to the United States Department of Justice.Rain Olson Daugherty was arrested Tuesday and charged Friday morning with robbing a San Francisco bank.On Nov. 29, 2018, 44-year-old Daugherty allegedly entered the East West Bank in the Sunset District and handed a teller a note demanding money in $50 and $100 denominations, according to the affidavit. He then reportedly said something to the effect of "calm down, just do it." The teller handed over about $9,000 in cash, according to the statement.A second teller, who had observed the robber pass the note, pressed the alarm and left to notify a bank manager of the robbery.Daugherty is currently under suspension without pay, according to documents filed with the court.He is facing a maximum statutory penalty of 20 years in prison, the DOJ said.