"We take the integrity of our criminal investigations and the reliability of our forensic testing very seriously,” L.A. County Sheriff Robert Luna said.

The Los Angeles County Sheriff’s Department says it will retest 4,000 DNA samples and open an internal investigation after learning that it used potentially flawed test kits for eight months

The department said they were using the faulty DNA test kits for eight months until the manufacturer notified them. Deputies said the defective kits were "not likely to have falsely identified any individual.