LA County Retesting 4,000 DNA Samples After Using Faulty Kits for Eight Months

The Sheriff's Department and District Attorney's Office are investigating the oversight and assessing the impact on criminal cases.

The Los Angeles County Sheriff's Department used defective DNA test kits from July 2024 to February 2025 due to an administrative oversight.
Approximately 4,000 DNA samples must be retested, but some may be too small to retest, potentially affecting prosecutions.
The faulty kits led to incomplete or suboptimal results but are not believed to have falsely identified individuals.
The issue arose after a manufacturer's warning letter in August 2024 went unnoticed, as it was sent to an employee no longer with the department.
An internal investigation is underway to address procedural gaps, while the District Attorney's Office collaborates to ensure transparency and evaluate the impact on justice outcomes.