The promise and perils of DNA evidence

Though many cases involving the 5,123 unprocessed kits have been closed, evidence in more than 400 crimes could still lead to suspects, officials say.

815 sexual assault cases with untested DNA and no suspects have been tallied so far; statute has expired on 51 of them.

The police union warns members that submitting genetic evidence could lead to invasions of privacy. Department officials say the practice is needed to investigate serious use-of-force cases.

By far the most reliable forensic science, it still has limits: Samples can be contaminated and may go untested for years. And collecting it may violate privacy laws.

California’s familial searching policy, the most extensive in the nation, looks for genetic ties between culprits and kin. Privacy advocates and legal experts are nervous.

The department plans a case-by-case review to see which sexual assault kits remain unexamined. The revelation follows reports of a similar DNA backlog at the LAPD.

Law enforcement agencies that had not used full allocations from previous years found their grants reduced despite an estimated 400,000 untested cases.

City officials acknowledge that the funding of the $700,000 effort is uncertain. The proposal is scheduled for a City Council vote Wednesday.