More than 50% of the cases reviewed by Waukesha County DA candidate Michael Thurston when he was a prosecutor in Milwaukee County ended up not being prosecuted by the office, according to numbers obtained by Wisconsin Right Now via an open records request.

These are the numbers provided by the Milwaukee County DA’s office:

“From the period of January 1, 2012 to December 31, 2015. PROTECT data reveals that Michael Thurston reviewed 778 total cases with 367 cases filed/closed. PROTECT data states that 411 cases were no processed. The limitations of PROTECT do not allow us to pull out data to determine if any cases were under review at the time Michael Thurston left the office,” wrote Sara Sadowski, the open records custodian for the Milwaukee County DA.

That means that, of the 778 total cases that Thurston reviewed, according to Sadowski, about 53% were not prosecuted – either by him or another prosecutor.

The latter part is an important caveat to the data; the office said it’s not possible to tease out for sure whether another prosecutor appeared on or made key decisions, in some of the cases. Sometimes in DA’s offices, prosecutors take over or handle cases for other prosecutors because they leave, are on vacation, or for some other reason. However, the data provides the best window available into Thurston’s performance when he was a Milwaukee County prosecutor before moving to the Waukesha County DA’s office. The cases represent cases he handled at least in part. We think that’s important, so we are sharing everything we know. We can’t obtain specific names of those not prosecuted because the Milwaukee County DA has historically refused to provide them to WRN; in fact, we filed a complaint with the state AG about that in the past.

What is a non-prosecution percentage? Police refer charges to the DA’s office, and a prosecutor is assigned to review the case. The non-prosecution percentage is the percentage of those cases that a prosecutor rejects, not choosing to file criminal charges.

Minimally, the numbers show that Thurston likely did not buck the Milwaukee County DA’s overall sky-high non-prosecution trend by going on a prosecution binge while he was there. In fact, the 53% non-prosecution percentage for those 778 cases generally mirrors Milwaukee DA John Chisholm’s office’s non-prosecution percentages on the whole. In 2022, the latest year available, Chisholm’s office has charged only 42% of referrals, according to the DA’s dashboard. In contrast, Waukesha County DA Sue Opper’s Office’s overall non-prosecution percentage has ranged from 5.8 percent to 9.7 percent from 2022 to present.

Opper is retiring, setting up a heated Republican primary between Thurston and prosecutor Lesli Boese on Aug. 13.

We previously reported that Michael Thurston has a much higher non-prosecution percentage in the Waukesha County DA’s office than his opponent in the race, Lesli Boese, and that’s held true over time. Since 2022, Thurston’s non-prosecution percentage averaged 21 percent. Boese’s non-prosecution percentage averaged only 1.6 percent, according to records obtained by Wisconsin Right Now through an open records request with Waukesha County DA Sue Opper’s Office.

The numbers out of Milwaukee County help fill out that picture.

Both are currently prosecutors in the Waukesha County DA’s office – he runs sensitive crimes, and she runs the drug unit. Thurston, as with Boese, is running on a tough-on-crime platform of protecting Waukesha County residents and both have obtained key endorsements, including from law enforcement. “I’m proud of my track record of leadership and experience and service, and firmly believe that these are the very qualities that Waukesha County residents expect in their next District Attorney,” his website says.

We filed open records requests for the Milwaukee and Waukesha County numbers after being urged to do so by Thurston supporters, who said his track record as a prosecutor mattered more than his past donations to Democrats. Thurston’s five donations to Democratic Milwaukee County DA John Chisholm, some of which came after he had already left that office for Waukesha in 2015, have caused controversy, as have his donations to Democrat Richard Cordray in the Ohio governor’s race, one of which came three weeks after former President Barack Obama endorsed Cordray. His comments in a debate that he would invite Democrats to help train prosecutors on election integrity have raised some eyebrows as has his refusal to condemn John Chisholm’s John Doe into Gov. Scott Walker’s campaign finance record when asked. Boese has outright called him a “RINO” in the debate.

Thurston is outspending Boese in the race due to at least $150,000 in loans that he gave his own campaign, per campaign finance records (she has spent $25,000). Her cause has been boosted by conservative Dick Uihlein’s group, which is running television ads raising concern about Thurston’s strength as a prosecutor, though.

Chisholm’s office’s sky-high non-prosecution rate has been the subject of repeated conservative criticism over recent years, and WRN has taken the lead in documenting it.

On July 31, we asked the Milwaukee County District Attorney’s office, for the number of cases referred to Thurston to handle; the number of cases he declined to prosecute; and the number of cases backlogged or still under review at the time he left the office.

To be sure, cases not prosecuted are just one way to measure the performance of a prosecutor; that’s why we asked for cases that were still under review too, as Thurston has made a big deal of the fact that Boese has a case backlog in Waukesha County and he doesn’t. The Milwaukee DA’s office says it has no data to track that metric, however. Boese has attributed that backlog, at least in part, to some defendants becoming confidential informants for law enforcement.

Thurston has also argued that he handled more jury trials than Boese has; she disputes the numbers and points out that she handles complex drug cases. She also co-prosecuted the massive Waukesha Christmas parade trial, which lasted at least a year.

He has argued that, in 10 cases, people waiting for a charging decision from Boese ended up re-offending; however, when we requested the names from Thurston so we could do a story on that angle, he did not respond. She stated in a debate that his percentage of amended and dismissed cases is higher than hers. You can read an exploration of different metrics in the race here.

Thurston has also argued that his role as a sensitive crimes prosecutor is different than hers as a drug prosecutor; he says that sometimes victims won’t cooperate and has noted that domestic violence and sexual assault cases are often difficult to prove. There is merit to that argument; DV and sexual assault cases can be notoriously difficult to win at trial.

We received a response from the DA’s open records person, Sara Sadowski, on Aug. 7.

Sadowski wrote, “According to our file, Michael Thurston was in the Milwaukee County District Attorney’s Office from November 2013 to December 26, 2015.” That’s slightly different from Thurston’s campaign website, which says, “In January of 2014, I began work with the Milwaukee County District Attorney’s Office, first as a domestic violence prosecutor, then as a sensitive crimes’ prosecutor.”

We asked Sadowski why the statistics provided date to 2012 when she says Thurston was hired in 2013. She explained that they went back farther in a good-faith attempt to give the fullest picture possible because Thurston likely took over some old cases that were opened previously when he started as a prosecutor. Thus, the numbers include some cases he inherited from other prosecutors.

Sadowski’s letter provided this context:

“I would like to first provide a bit of history as to how we store the numbers and data that you request. What you requested is only available in our PROTECT system. The PROTECT system is not a data analysis system and was created for a different purpose,” she wrote. “Before February of 2009, the District Attorney’s Office relied, solely, on paper files. In 2009, the State of Wisconsin DA-IT implemented a digital case management system, called PROTECT, for all District Attorney’s Offices in Wisconsin. Once PROTECT was implemented, all case-related documents had to be entered into and generated through the PROTECT system.”

The letter noted, “PROTECT was designed to interface with the Wisconsin Circuit Court Access Program (CCAP). PROTECT, and the interface were deployed in stages. In 2020, the District Attorney’s Office began to transition to a fully digital (paperless) file system. There are two areas in PROTECT where a case can be assigned to a prosecutor. First is the reviewing ADA, and second is the assigned ADA. Those two categories may be the same prosecutor or different prosecutors. Additionally, those assigned areas can be changed at any time, by any office staff, and those assignments are changed any time there is a change in the prosecutor that is responsible for handling the case, either before or after criminal charges are issued.”

She added, “There is no way to capture the data as it would have appeared at the time Michael Thurston was in the Milwaukee County District Attorney’s Office, nor is there a snapshot that could be obtained for any particular date. Additionally, when someone leaves the office it is customary to change the assignments to the individual that assumed responsibility for the cases that are still open. This can also occur with internal moves within the office. With this being said, we were able to pull data that you requested out of the PROTECT system. However, it is with the caveat that, it is as the data appeared on August 1, 2024, and likely does not capture the full breadth of data from the time Michael Thurston was in the Milwaukee County District Attorney’s Office.”