The woman carefully selected a beverage and set it on the counter before pointing a gun at a convenience store clerk and demanding money.
Tacoma police said the 36-year-old woman did it twice in two days. For the third robbery, she skipped the drink and went straight for the cash.
Pierce County prosecutors have charged the woman with three counts of first-degree robbery. She has not been arraigned.
The holdups took place within 11 days in January. Police quickly recognized similarities in the holdups but had no suspects.
That changed Jan. 21 when the woman robbed a mini mart in the 4000 block of East Portland Avenue.
After the holdup, a witness followed her outside and demanded she return the money, according to charging papers.
He said the woman pointed a gun at him and told him to go away. He complied but noticed she discarded a sweatshirt in the garbage can.
Detectives later tested the sweatshirt for DNA and traced it to the woman, who was being held in the Pierce County Jail on unrelated charges in an indecent exposure case.
When they interviewed her last week, detectives said she admitted to the robberies and claimed she used a BB gun rather than a handgun.
Stacia Glenn: 253-597-8653