The former attorney general of Arizona, Mark Brnovich, failed to release documents that showed his office’s investigation into the 2020 election did not find evidence of widespread fraud in the state’s most populous county.

The Washington Post reported on Wednesday that Brnovich would not turn over public records that detailed his investigators’ findings. His successor, the Democratic attorney general Kris Mayes, released the records, which showed several reports that debunked rampant claims of election problems in Maricopa county.

Brnovich, a Republican, was running for US Senate in 2022 while his office oversaw an investigation into the 2020 election. He released two reports related to the work – one that showed just one example of a dead person voting and one “interim report” that made nebulous, unfounded criticisms of the county’s elections.

But the unreleased reports show Brnovich’s investigators did not agree with some assertions he made publicly, such as that the county did not follow proper signature verification procedures or that the county had not been responsive to his requests for information.

In an interview with the Guardian on Wednesday, Mayes said her office discovered a bunch of unfulfilled records requests upon taking over in January. She also wanted to find any potential final report for the 2020 investigation, which was not found.

Her office released two additional interim reports and an investigative summary, which are all publicly posted on the attorney general’s website now.

“This office has a solemn duty to be honest and transparent with the people of Arizona,” Mayes said. “The dark cloud cast over the 2020 and 2022 elections because of the insane conspiracy theories perpetrated by high-profile election deniers could have and should have been stopped, especially as it related to Maricopa county and its elections officials. I believe the people of Arizona had a right to know this information before the 2022 election. Unfortunately, that didn’t happen.”

The investigation is considered closed, though there are hundreds more documents going through the redaction process that will be released once the office has completed that process.

The office under Brnovich spent about 10,000 hours on the investigation and each of its 60 investigators spent at least some time on it, the Post reported.

Mayes said it is hard to put a dollar figure on how much that cost the state or taxpayers, but the whole effort was clearly a “distraction from the core mission of this office”.

“But I also want to say I’m incredibly proud of the work the agents and support staff who worked on these investigations did. They did so diligently, thoroughly and professionally, as they do all of their work here,” she said.

Mayes said she did not get any insight into why Brnovich did not release the information while he was in charge, saying Brnovich would need to answer that for himself. Brnovich did not respond to a request for comment.

“This kind of failure to release information to the people of Arizona is not how this office will operate moving forward under my leadership,” Mayes said. “My administration will be truthful and transparent.”

The Post report compelled elections officials throughout the state to comment on the revelations, especially those who Brnovich had previously criticized publicly.

Clint Hickman, the chairman of the Maricopa county board of supervisors, said he was “absolutely disgusted” that Brnovich concealed reports on the 2020 election and applauded Mayes for finally releasing the documents. He implored people who care about elections to read the reports.

“This was a gross misuse of his elected office and an appalling waste of taxpayer dollars, as well as a waste of the time and effort of professional investigators,” Hickman said in a statement.

He pointed to the onslaught of threats and harassment the board, elections officials and election workers have faced while false claims of impropriety in the 2020 election lingered for years.

“For three years, my colleagues have been called traitors, cheaters, and liars … and those are just the names I can print,” Hickman said. “It has been absolute hell on all of us, but I would do it again in a second and I believe that every member of this board would do it again because all of us stayed within the law.”

Stephen Richer, the county’s Republican recorder, noted two elements of the reports where investigators contradicted Brnovich’s interim report by saying the county had been responsive and followed signature verification procedures. Those notes from investigators “distinctly show the ways in which our office cooperated with and supported the attorney general’s office in the development of last year’s interim report,” Richer said.

Arizona’s Secretary of state Adrian Fontes, a Democrat who in 2020 was the Maricopa county recorder, said he was “deeply disappointed by the wasteful and pointless actions by a top law enforcement official who diverted thousands of hours of staff time to pursue unfounded allegations of election fraud”.