The Lake County district attorney has determined Sheriff Frank Rivero lied during a 2008 investigation and therefore must be on a list of law enforcement officers whose court testimony may be questionable.

District Attorney Don Anderson said in a report that Rivero "did not tell the truth and made material misrepresentations" after a 2008 confrontation when Rivero shot at but did not hit a potentially violent man holding pepper spray.

The finding means that Rivero is now tagged as a so-called "Brady officer," a term stemming from the U.S. Supreme Court's 1963 Brady vs. Maryland decision that said the defense must be told when an officer has a history of making false statements.

Rivero took the unusual step of challenging the district attorney's finding in a civil suit filed Feb. 28, claiming that the investigation into his statements was unfair and violated his due process rights.

"Allegations against my credibility are absolutely damaging, but they're not true," Rivero said.

Prosecutors must now weigh how crucial material testimony from Rivero is to a case, Anderson said.

"When it comes to putting on a trial and evaluating a case, we will have to ask, 'Is it a case worth going forward with? What's a jury going to think?' " Anderson said.

Anderson's decision to put Rivero on the Brady list came to light Monday during a public hearing when a judge denied Rivero's request that the documents be kept under seal while he challenges the report.

Judge William Lamb said that it's in the public interest to have the facts regarding an elected official emerge in open court.

The decision prompted the immediate release of Anderson's report, finished last month, that outlines conflicting statements from Rivero about whether he saw pepper spray in a man's hand and how the man moved before he fired one shot.

Anderson began the investigation in March 2011 when a former deputy, Michael Sobieraj, who was at the scene, alerted his office that he believed Rivero lied during the 2008 investigation.

The incident occurred Feb. 19, 2008, at a home in Whispering Pines, an unincorporated community off Highway 175.

Rivero, then a deputy, and Sobieraj went to the home in response to a call reporting "a continuing domestic dispute," according to Anderson's report.

The report highlights that Rivero's statements about what happened changed over time and also differed from two other witnesses.

Rivero entered the residence of Julia Exline to confront her ex-boyfriend Victor Rodin, who came out of a bedroom carrying a lighter in one hand and pepper spray in the other.

Exline, who was behind Rivero, said the then-deputy told Rodin to "drop the pepper spray" several times. Sobieraj also told investigators he heard the same thing.

Rivero told Rodin to turn around and put his hands on his head, but Rodin refused, later telling investigators he was afraid of Rivero, who he said was "in a rage." Instead, Rodin stepped back into the bedroom and Rivero fired a shot. He missed.

Rodin locked the bedroom and climbed out a window.

Later that day, Rivero told Sgt. Gary Hall that Rodin had pepper spray in hand, which the sergeant said stuck in his mind because it's against department policy to shoot someone because they're in possession of pepper spray.

Rivero later would tell investigators that he didn't know if Rodin was holding pepper spray and couldn't see his hand. He also said Rodin "bolted back," turned and kneeled behind a bedroom wall, "reached down and grabbed something" then came up "in a hostile fashion" and pointed something at him, according to the report.

"It is unlikely the account of the incident described by deputy Rivero is accurate," Anderson said in the report.

Rivero, reached by phone Tuesday, said he was telling the truth. He said he intended to continue a court challenge of the way Anderson's office investigated the matter, a process he called unfair.

"I'm going to continue to run the department and continue to do what I need to do," Rivero said. "I'm very confident that I will be vindicated; the truth is the truth and it always comes out in the end."

For Rivero, the designation may not carry the heavy penalty it does for officers working in the field.

As sheriff, Rivero's work is primarily administrative and he is unlikely to testify as frequently as rank-and-file deputies within the Sheriff's Office, for whom the designation could be devastating.

Still, the Brady designation has already come up in court.

Last week, a judge ordered prosecutors to give the defense information about Rivero's credibility for a case against three Hells Angels facing criminal charges stemming from a 2011 fight.

"It's a burden on the Deputy District Attorney who is prosecuting the case," Anderson said.

You can reach Staff Writer Julie Johnson at 521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.