(AP) — The U.S. Justice Department said Thursday that the sheriff’s department and prosecutors in Orange County, California, ran an extensive jailhouse informant program for years that violated the rights of criminal defendants.

The federal agency, which began investigating the allegations in 2016, issued a lengthy report detailing Orange County authorities’ use of the informants from 2007 to 2016 and their failure to release information, as required by law, about incriminating statements gathered by the snitches to lawyers for the accused.

The report said the district attorney’s office had failed to conduct a full probe of the scandal that rocked the county of 3 million people and said it should “establish an independent body to conduct a more comprehensive review of past prosecutions involving custodial informants.”

Orange County, which saw a number of criminal cases upended once the allegations came to light, stopped using the informants in 2016, the report said.

“The failure to protect these basic constitutional guarantees not only deprives individual defendants of their rights, it undermines the public’s confidence in the fundamental fairness of criminal justice systems across the county,” Assistant Attorney General Kristen Clarke said in a statement.

The report comes years after the allegations of prosecutorial conduct arose in the case of a man who killed eight people in a 2011 shooting in a hair salon.

Scott Dekraai pleaded guilty to the murders but was spared the death penalty over authorities’ use of an informant to cull information from him while he was represented by a lawyer — which was unearthed when his attorney flagged that the snitch had also been involved in another high-profile case.

In a separate instance, a gang member charged with a 2004 killing took a plea deal and a shorter prison sentence after an earlier conviction was set aside over concerns that prosecutors had failed to share critical evidence.

Messages seeking comment were left for the Orange County district attorney’s office and sheriff’s department.

Authorities can use jailhouse informants but can’t have them deliberately elicit information from defendants once they are represented by lawyers. In addition, prosecutors are required to turn over evidence to defense attorneys that could be seen as favorable to their clients.