ST. LOUIS (AP) — St. Louis' top prosecutor faced a primary challenge on Tuesday after drawing criticism from President Donald Trump for filing charges against a couple who displayed guns at protesters marching near their home.

Kim Gardner, the city's first Black circuit attorney, also received national attention when she filed criminal charges against Missouri's governor in 2018. She's being challenged in the Democratic primary by Mary Pat Carl, who is white and once served as the city's lead homicide prosecutor. The winner will be heavily favored in November over the lone Republican running, Daniel Zdrodowski. St. Louis is overwhelmingly Democratic.

Polls closed at 7 p.m., but St. Louis election results tend to be slow so it's uncertain when the race will be called.

Gardner, 44, defeated Carl and two other candidates in the 2016 primary election. She has shaken up the city's criminal justice establishment, initiating reforms that have included using diversion programs instead of incarceration, halting prosecution of low-level marijuana crimes and reducing the number of people incarcerated.

“We have to look at how we address justice and fairness for all, and I believe that’s what we’ve been doing,” Gardner said in an interview with The Associated Press.

She also drew the ire of police leaders when she developed an “exclusion list” of officers who can’t serve as primary witnesses because of unspecified credibility concerns. Critics also have accused her of falling short in convicting violent criminals in the city with one of the nation's highest murder rates.

Her decision last month to file felony unlawful use of a weapon charges against Mark and Patricia McCloskey drew strong rebuttals from Trump and other leading Republicans.

Several hundred demonstrators were marching to the home of Mayor Lyda Krewson on June 28 when they veered onto a private street where the McCloskeys lived. He came out with a semi-automatic rifle and she had a semi-automatic handgun.

Gardner said the display of weapons during an otherwise peaceful protest risked bloodshed. The McCloskeys said they felt threatened. The case is still pending.

Trump criticized Gardner on Twitter and in interviews. Gov. Mike Parson said he’ll likely pardon the couple if they’re convicted. Sen. Josh Hawley of Missouri asked the U.S. Department of Justice to investigate Gardner. Republican Missouri Attorney General Eric Schmitt asked a judge to throw out the charges.

It wasn't the first time Gardner took on a high-profile case that garnered national attention.

In 2018, she charged then-Gov. Eric Greitens, a Republican, with felony invasion of privacy, accusing him of taking a compromising photo of a woman during an extramarital affair and threatening to post it if she spoke of the affair.

Greitens admitted to the affair but denied any crime. The charge was later dropped, but Greitens, who also was facing unrelated ethics complaints, resigned in June 2018.

Carl, 43, is among the critics who have accused Gardner of wasting time and money on the high-profile cases rather than doing more to put violent criminals behind bars.

Carl served 14 years in the circuit attorney's office. In an interview with The Associated Press, she pledged to send a prosecutor to the scene of every homicide, both to show support for the victim and to encourage witnesses to cooperate.

“If people don’t feel safe in their homes, if children can’t play in their yard, nothing else matters,” Carl said. "We have to stop the violence.”

Despite the criticism, Gardner has had plenty of support. The city’s Black community in particular has lauded her reforms.

Gardner has long contended she’s the victim of race-based attacks. In January, she filed a federal lawsuit accusing the city government, along with the biggest police union and others of a coordinated and racist conspiracy aimed at forcing her out of office. The lawsuit also accused “entrenched interests” of intentionally impeding her efforts to change racist practices.