In March 2025, the Los Angeles County Sheriff's Department (LASD) announced it will retest 4,000 DNA samples due to the use of faulty testing kits over an eight-month period.

The issue was discovered on March 23, 2025, when a supervisor in the department's Scientific Services Bureau found a warning letter from the manufacturer that had gone unaddressed.

Despite the warning, the defective kits were used from July 2024 until February 2025, potentially impacting various criminal investigations.

An internal investigation has been launched by the Sheriff's Department to evaluate the situation, assess the impact, and improve existing protocols to prevent future occurrences.

Once the assessment is complete, LASD will notify all impacted law enforcement agencies.

The situation is expected to affect other law enforcement agencies, including the LA County District Attorney's Office, which is collaborating with LASD to assess the impact on the criminal justice process.

District Attorney Nathan Hochman emphasized the importance of maintaining trust in the criminal justice system and pledged to make decisions based on the facts as they emerge.

The L.A. Sheriff's Scientific Services Bureau is currently evaluating the extent of the impact on criminal cases and the reliability of forensic testing.

Sheriff Robert Luna reiterated the department's commitment to the integrity of criminal investigations and pledged immediate corrective actions.

While the faulty kits may have resulted in incomplete or suboptimal results, officials believe they are unlikely to have wrongfully identified any individuals involved in cases.

Public defenders' union president Brooke Longuevan expressed concerns about the implications for delayed trials and the erosion of public trust in the criminal justice system.

The specific company that produced the faulty test kits remains unidentified in the released information.