top of page
  • Writer's pictureJared Keenan

County attorneys are powerful: Their prosecuting pasts matter

By: Jared Keenan, ACLU of Arizona Criminal Justice Staff Attorney

For the first time since 1996, Pima County will elect a new county attorney. The county attorney holds the most powerful position in the criminal legal system, deciding who goes to prison and for how long.

Three Democrats want to replace long-time county attorney Barbara LaWall: Laura Conover, Mark Diebolt Jr., and Jonathan Mosher. With no Republican challenger, the race will all but be decided in the August 4 primary.

The ACLU of Arizona does not endorse or oppose candidates. Rather, we encourage voters to assess candidate's records and values so they can make an informed choice.

That's why we think it crucial to inform voters about troubling misconduct in two candidates' pasts, only discovered through a years-long investigation into prosecutor misconduct.

The ACLU of Arizona is bringing this information to light because it points to a systemic problem within the criminal legal system: it is notoriously difficult to hold prosecutors accountable for misconduct. And it is equally difficult for the public to find out about it.

In 2014, the Arizona Court of Appeals found that Jonathan Mosher committed misconduct during a murder trial when he was a prosecutor in the Pima County Attorney's Office.

The case involved a man charged with felony murder, a type of first-degree murder, the most serious charge on the books. It can result in a death sentence or life imprisonment. But Jonathan Mosher didn't tell that to the jury in the case. Instead, he untruthfully told them that felony murder was a "less serious form of murder" than first-degree murder.

Mosher's false and misleading statement to jurors led the Arizona Court of Appeals to overturn the man's conviction. The court called Mosher's statements "improper" and found his action to be "misconduct." A new trial was ordered at the taxpayers' expense.

In 2015, Mark Diebolt Jr. was reprimanded by his employer, the Pima County Attorney's Office, for violating his ethical duties as a prosecutor. According to the letter of reprimand, a criminal defendant told Diebolt he knew someone else had shot a man in an unrelated murder case. Diebolt didn't inform his supervisor who was prosecuting the murder case and the information was never given to the defense attorney involved in the case. This crucial information was revealed months later, after the criminal defendant had been convicted and sentenced. In the letter of reprimand Diebolt was told, "Your lack of attention to detail and failure to exercise due diligence on this issue is inexcusable for a prosecutor with your years of experience."

Misconduct like this comes at a huge cost. The constitutional rights of the accused are violated. People impacted by crimes are dragged through additional proceedings and taxpayer's foot the bill.

The ACLU of Arizona discovered Mosher and Diebolt's misconduct by digging through appeals court records and other public records we obtained from county attorney's offices before Mosher or Diebolt had filed their candidacy. The goal of our investigation was solely to shine light on how prosecutors are rarely held accountable for misconduct.

Mosher was not named in the appeals court record. In Diebolt's case, the letter of reprimand was heavily redacted. We identified them both by comparing details of their cases with data from the Pima County Attorney's Office's case management system which we obtained through a public records request.

The complex process through which this information was uncovered demonstrates precisely why voters should demand their next county attorney change the culture of secrecy within county attorney's offices. Because prosecutors operate in a black box and oppose transparency, most voters would be unable to access this important information about two candidates running to become the most powerful elected official in Pima County's criminal legal system.

Again, the ACLU of Arizona does not endorse candidates. We will not tell you how to vote. But we encourage voters to demand an elected county attorney who will implement stricter ethical guidelines for prosecutors and adequately discipline those who commit misconduct. Voters must demand a county attorney who will be transparent, letting the people know when prosecutors violate the rights of the accused and waste tax dollars. Voters must demand an elected county attorney who rejects the "win at all costs" mentality that permeates prosecuting agencies around the state and instead embraces a culture of fairness, integrity, and smart justice.

Jared Keenan is the criminal justice staff attorney for the ACLU of Arizona. He can be reached at or on Twitter @realJaredKeenan.

794 views0 comments


bottom of page