A proposal to restrict how San Francisco police handle DNA moved forward Monday in response to outrage over the department using evidence from a rape kit to arrest a woman in an unrelated crime.
The Board of Supervisors Rules Committee unanimously supported Supervisor Hillary Ronen’s legislation to curtail the department’s practice of storing all DNA evidence in a quality control database. While meant to ensure samples aren’t contaminated, the practice led to a woman being identified as a suspect in a property crime after police matched evidence from her rape kit to an unknown sample collected from a crime scene.
Ronen’s legislation aims to prevent similar situations from occurring by prohibiting police from storing victim DNA in the database and requiring police to purge its database of existing victim DNA. Police would also be barred from storing DNA collected from scenes in the database for longer than 60 days.
“We need to send a clear message that this disturbing violation of victim privacy will never happen again in San Francisco,” Ronen told the committee.
District Attorney Chesa Boudin first raised the alarm in February after discovering the practice led to an arrest. Boudin dropped a felony case against the woman in response, saying the practice likely violated constitutional protections against unwarranted searches and seizures. The district attorney also worried the practice would dissuade rape victims from cooperating with police.
Police Chief Bill Scott has already implemented policies to prevent the situation from happening again, including a 60-day retention period for samples entered into the quality control database.
Acting Crime Lab Director Mark Powell told the committee Monday that the department is already in compliance with the legislation. The department has purged the database of known victim DNA samples, Powell said.
The Crime Lab began keeping the database in 2015 to ensure it didn’t mislead investigators or incorrectly enter samples into a federal database of criminal DNA known as CODIS, or the Combined DNA Index System.
“The whole purpose of that was to monitor for contamination,” Powell said. “To make sure that we as a lab didn’t make a mistake and we spilled DNA from one sample in an evidence case and then it ended up contaminating another case.”
The problem arose when the Crime Lab began matching victim DNA entered into the system to unknown samples from crime scenes. As the database grew, the lab decided to start reporting those matches to investigators in 2019.
“It was never meant to be an investigatory thing,” Powell said. “It was more the lab has information, what do we do with it?”
So far, the woman’s case is the only known arrest that resulted from the practice.
While the department has taken corrective measures, Ronen said, the Board of Supervisors should still cement the restrictions in local law.
State Sen. Scott Wiener and Assemblymember Phil Ting also introduced legislation in February to address the issue across California.