LaSonya Wells, whose arrest on kidnapping charges for stealing a prominent local politician’s cell phone raised questions about race and fairness in San Francisco’s judicial system, is back in jail.

Once again for robbery. And at the same location.

Wells was convicted last year of grabbing then-Supervisor Scott Wiener’s iPhone as he was walking near the 16th Street BART Station. After being robbed, Wiener quickly negotiated with Wells — and her 20-year-old son — to accompany him to a nearby Wells Fargo ATM, where he withdrew $200 in return for the phone.

In addition to theft, the district attorney also charged Wells with kidnapping for ransom, a charge that could have sent her to prison for life.

At the time, Public Defender Jeff Adachi called the kidnapping charge “positively medieval” and said that prosecutors may have been motivated more by Wiener’s status than the facts of the crime.

The case ended with a deal: Wells pleaded guilty to felony extortion, with credit for time served.

Fast-forward to June 28, when Wells was arrested outside the same BART station where she robbed Wiener. This time, she and a male accomplice allegedly tried to rob a man of $100 and steal his cell phone in what may have been a drug deal gone bad.

The incident was caught on a nearby surveillance video camera.

Wells, who has a long history of substance abuse, was booked for felony robbery and misdemeanor possession of a cocaine-based substance. She posted a $100,000 bond. However, she subsequently missed her court appearances and a bench warrant was issued.

“I have no idea why she missed court,” said Assistant Public Defender Eric McBurney, who is representing Wells.

She was picked up during a traffic stop on Sept. 18 and is back in custody.

“I really hoped she would get her life back together and get on track,” Wiener said. “It’s disappointing to hear she is in trouble again.”

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX-TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross