LA County Sheriff's Department has been using potentially faulty DNA test kits for months

LOS ANGELES (CNS) -- The Los Angeles County Sheriff's Department announced Wednesday it plans to re-test about 4,000 DNA samples after learning the agency used testing kits over a roughly eight-month period that were found by the manufacturer to occasionally deliver incomplete results.

According to the department, officials at the Scientific Services Bureau learned only Monday about a notice that was sent to the agency last year by a DNA testing kit manufacturer stating that "a specific lot of kits were prone to intermittently poor performance with potential to cause incomplete results or profiles."

The notice was sent to the department on Aug. 28, 2024, but it was directed to a person who was no longer with the department.

"I'm very concerned about this issue," said Sheriff Robert Luna. "I'm demanding to find out what happened, how it happened, when it happened, why it happened."

The notice by the manufacturer recommended that the use of the affected kits be discontinued, but the department continued using them for about eight months, between July 2024 and February 2025. It was unclear exactly how many criminal investigations may have been impacted by the use of the affected kits.

The sheriff's department contended in a statement, however, that "the use of the affected kits may have led to incomplete or suboptimal results, but is not likely to have falsely identified any individual."

But to determine the possible extent of the issue, the department will re-test about 4,000 samples, although such re-testing may not be possible in some cases due to the limited sample sizes available.

"They're going to prioritize cases, anything that's a murder, sexual assault, will go first," said Luna.

Sheriff's officials said the department has begun an internal investigation into the matter, and it will "re-examine existing protocols, identify potential gaps and implement corrective measures to prevent this from occurring again."

The department noted that other law enforcement agencies might have also been affected, including the District Attorney's Office.

"Upon learning of this issue concerning forensic testing on Monday, the District Attorney's Office has immediately started working with the Sheriff's Department to assess the scope of the situation in order to ensure that those involved in criminal justice process - defendants, defense counsel, victims, prosecutors, law enforcement, the courts and the public - are kept abreast of developments and in a position to make informed decisions on any actions that may need to take place," District Attorney Nathan Hochman said in a statement.

"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. Ensuring the integrity of the criminal justice process to build and maintain trust in its outcomes is paramount as we go forward."

The L.A. County Public Defender's Office said the batch of defective kits erases trust in the criminal legal system. Luna said he is in contact with the district attorney's office and plans to notify those impacted including defendants and victims.

"I am told that none of these cases had gone to trial yet, but I need to confirm all that," said Luna.

Luna would not discuss the testing kits' manufacturer or disclose how long the department has worked with the company.

"We're going to fix this, and not only are we going to fix this, we're going to make sure this never happens again. It's not acceptable," he said.

The sheriff said he's unsure how long the re-testing process will take and noted that although he wants answers as soon as possible, it's more important to make sure the tests are done right.

City News Service, Inc. contributed to this report.