Contra Costa County's incumbent sheriff doubled down on support for an ex-deputy convicted of assault for a fatal on-duty shooting in Danville, calling the charges politically motivated, while his challenger criticized existing sheriff's office policy for contributing to why the encounter turned deadly, as the two candidates squared off at a debate Tuesday.

Sheriff-Coroner David Livingston faces a challenge to his seat for the first time in more than a decade, running in next month's primary election against Benjamin Therriault, president of the Richmond Police Officers' Association.

The opponents answered questions about the Danville deputy's conviction and a range of other topics during a public safety candidates forum at Diablo Valley College on Tuesday evening that also included a separate debate between district attorney candidates. The event was moderated by DanvilleSanRamon.com publisher Gina Channell Wilcox and editor Jeremy Walsh.

"I'm running for sheriff because we are devoid of leadership in this county when it comes to law enforcement," Therriault said in his opening statement. "The sheriff's office should be leading the way, and for far too long, it has been following. I want to change that, I want to reverse that; I want Contra Costa to be the leader of law enforcement in the state of California."

Therriault, a police officer in Richmond and a first-time candidate, has entered the race with a platform aimed at appealing to voters seeking police oversight, reform and change. Livingston has taken a platform that seeks to highlight his work over 11 years in office and rejects what he says are the political motivations behind calls for increased accountability and reform in policing by some county voters amid recent controversies involving deputies.

Tensions between the two candidates were high at times, with the evening's debate seeing them voice opposing positions in response to questions involving what transparency and accountability should look like in the office, the morale of current employees, and approaches to recruitment and retention.

One particular elephant in the room that was discussed early was the conviction of Andrew Hall, a now-former deputy from Livingston's office who was recently sentenced in the shooting death of 33-year-old Laudemer Arboleda following a slow-speed car chase in Danville in November 2018. Criminal charges were filed against Hall by the DA's office after 2-1/2 years -- and only after Hall, who was cleared to return to duty by Livingston, fatally shot another man, Tyrell Wilson, on-duty in Danville in March 2021.

Livingston, who has run unopposed since he took office 2011, has come under fire for remarks in a leaked internal letter saying that Hall's sentencing marked "a sad day" and voicing support for the former deputy who was transferred to a state prison for his six-year sentence last month.

On Tuesday, the sheriff doubled down on his support for Hall, and made an effort to provide further context to his position.

"I think the criminal charges were absolutely political," Livingston said. "She (District Attorney Diana Becton) placed it on her Facebook ad, arms crossed 'I charged a police officer' -- it's reprehensible in my opinion. The first officer charged in Contra Costa County."

"This isn't him kneeling on someone's neck for nine minutes -- the horrible case we're all familiar with. This was a split-second decision," Livingston continued. "That's why I've said what I've said about that. I'm a leader of the agency and I support his actions if he behaves honorably, he acts within policy and he obeys the law, and I believe he did all those things."

Therriault contended that Hall's conviction and Arboleda's death could have been prevented by different policies in the sheriff's office, which Livingston found Hall acted within according to his office's internal investigation into the shooting.

"Experience would have led you to have better policies that would not have put Officer Hall in that predicament in the first place," Therriault said. "It's the policies that come from the top and transcend down to the bottom to the deputies who actually have to do the work. And when they have to go out and do the work, they follow the policies and procedures of the agency. And if things had been done differently, perhaps that incident never would have happened, and it shouldn't have happened."

In a rebuttal, Livingston contended that Therriault's remarks about Hall were inappropriate coming from a fellow law enforcement officer.

"That's ridiculous, and it's unfortunate that a fellow officer would question the actions of another police officer," Livingston said.

The two candidates also butted heads when asked what transparency, accountability and oversight should look like in the sheriff's office, with Livingston saying he supported existing forms of oversight, but that he was not interested in an appointed body established for that purpose nor did he think the Board of Supervisors would be.

"As far as being transparent and oversight, we already have oversight from the Bureau of Prisons, from the attorney general, from the civil grand jury, and the sheriff as set out in the Constitution is directly responsible to the voters," Livingston said. "So I am leery of having a group come in that would then say, 'These are the priorities that the sheriff's office should be pursuing'."

A question about property crime prevention amidst high-profile incidents such as a mass robbery at Nordstrom's in Walnut Creek, and ongoing catalytic converter thefts throughout the Tri-Valley, also sparked a contentious discussion.

"We are aggressively investigating these cases, and when we had for example the situation in Walnut Creek, I immediately called the chief, and I work very well with all the chiefs throughout the county, and I said I want to offer my services at no cost to increase patrol, to have greater vis, to hopefully make shoppers in that area…comfortable, but also to be a deterrent…" Livingston said.

Livingston also called for a "partner in the DA's office that will charge these cases," alleging that this has not been the case under Becton.

Therriault agreed that "organized retail theft is a serious problem," and said that the community was clearly calling out for solutions. However, he argued that data and crime trend analysis were powerful tools for prevention that he said Livingston hadn't fully taken advantage of, and pointed to the loss of crime analysis professionals in the current office.

"Every working cop in the Bay Area was watching how in different … high end commercial districts, there were these organized retail thefts," Therriault said. "It should come as no surprise that it was going to come eventually to Contra Costa County, and sure enough it did. The Sheriff did something about it after, which is great, but I think we probably should have had some people in place beforehand."

One area on which the candidates shared common ground was committing to a tough stance on gun violence, including the rise of Polymer 80 "ghost guns" that can go unregistered and untraced -- except for Therriault's support of the program Operation Ceasefire as an example for prevention, which Livingston called "Richmond's idea of paying people not to kill each other."

"When you talk about violent crime with a firearm, we're going to make arrests in Contra Costa County," Livingston said. "We're not going to hold their hand, give them a paycheck, say please don't shoot somebody," Livingston said.

Therriault did push back at the sheriff's characterization of the Richmond program.

Although topics of discussion ranged from approaches to gun violence, mental health and property crime, Hall's recent felony conviction -- and Livingston's ongoing and vocal support of the deputy -- came up in several of Livingston's responses, including one on employee morale.

"Now I was criticized for saying I have someone's back in an internal memo," Livingston said. "But if you took the time ... what it actually said, if you read it, was that if you obey the law and you follow policy, follow procedure. Not just I've got your back generally. There's much more to that memo. And I think people appreciated having a leader that doesn't just throw people under the bus but stands behind their people, and I do that."

"However, if they are out of line, if they've committed an offense, they will be held accountable," Livingston added, before he paused briefly to address a woman in the audience whom he said was shaking her head at him. The audience of several-dozen onlookers were seated in the round with the candidates and moderators at a small table in the center.

Therriault contended that Livingston's response to Hall's conviction and sentencing, rather than boosting employee morale or aiding in retention and recruitment, were emblematic of an office that is "out of touch," and "not where society wants to be."

"The criminal justice system has made many changes and we continue to make changes and improvements," Therriault said. "But in order to do that, we need someone who actually wants to lead, and wants to embrace that cutting edge and embrace being part of the future and not the past."

The forum was sponsored by the San Ramon, Danville Area, Brentwood, Walnut Creek, Lafayette and Concord chambers of commerce, as well as DVC. The two candidates will continue their campaigns in the coming weeks, ahead of the upcoming June 6 primary election.