Faulty DNA test kits forces LA County Sheriff to review cases

After using defective DNA testing kits for eight months, the Los Angeles County Sheriff's Department said it would review its recent criminal cases and thousands of samples. 

The agency's Scientific Services Bureau used the faulty kits from July 2024 through February 2025, according to LASD. The manufacturer notified the department about the defective batch of DNA testing kits on Aug. 28, 2024. However, the letter was forwarded to a person who no longer worked with the Sheriff's Department, according to deputies. Seven months after the manufacturer sent the letter, a supervisor overseeing the bureau noticed the manufacturer's advisory on March 24, 2025. 

"We take the integrity of our criminal investigations and the reliability of our forensic testing very seriously," said Los Angeles County Sheriff Robert G. Luna. "We are committed to thoroughly addressing this important issue, ensuring transparency, and taking immediate corrective action to protect the accuracy of ongoing and future cases. The Sheriff's Department is working diligently to assess the impact and to prevent such situations from occurring again."

The Sheriff's Department did not immediately know how many cases were affected by the faulty kits. The Scientific Services Bureau will retest roughly 4,000 DNA samples, but some specimens because they are too small, deputies said. The manufacturer told deputies the defective kits could have led to incomplete or suboptimal results but were unlikely to have falsely identified someone, according to the Sheriff's Department. 

Deputies said the issue will impact other law enforcement agencies, including the LA County District Attorney's Office. District Attorney Nathan Hochman said prosecutors have been working with the department to understand the potential impact on the criminal justice process. He added that he will keep everyone involved in the process, including defendants, victims, courts and law enforcement, informed about the latest developments. 

"We will follow the facts in whichever direction they take us on any individual case and make decisions that are in full accordance with the law on how to remedy any particular situation that requires such remediation," Hochman said. "Ensuring the integrity of the criminal justice process to build and maintain trust in its outcomes is paramount as we go forward."  

Once its assessment is finished, the Sheriff's Department will notify affected law enforcement agencies.