Keith Davis was accused of murder. Now he’ll face a fourth trial to prove he didn’t do it.

Kelly Davis was in Baltimore Circuit Court on Monday, bracing for the worst. Her husband, Keith Davis Jr., was either going to be sentenced to prison for a homicide he had denied committing or granted a new trial. The future of her family hung in the balance. Prosecutors had alleged that Keith Davis, 26, was responsible for the 2015 shooting death of a security guard. He was convicted in October, and he was facing a sentence of 50 years in prison.

But after the trial, Davis’s lawyer, Latoya Francis-Williams, said she discovered that a prosecution witness, a fellow inmate at the prison where Davis was held, wasn’t exactly reliable. The inmate, who testified that Davis bragged about being a killer, was, in Francis-Williams’s words, a “gangland enforcer and a notable serial killer” who “evidence suggests . . . has been parading around the country testifying in homicide cases in order to gain leniency for his gruesome crimes.” To Francis-Williams, it was clear the inmate had no credibility whatsoever.

On Monday, Judge Lynn Stewart Mays found that prosecutors had inappropriately “sanitized” the inmate’s background. Instead of carrying on with the sentencing, she granted Davis a new trial.

Kelly Davis rushed from the courtroom, ecstatic over the judge’s ruling. But she was still shaken by the close call.

“If I wasn’t living through this, if it wasn’t happening in my life, I wouldn’t believe it,” said Davis, a human resources specialist.

The trials and retrials come as Baltimore moves forward with a plan to overhaul the police department. A damning Justice Department investigation of the department, announced last year, described a city where police routinely violate the constitutional rights of citizens, African Americans particularly. As a result of what the report called “systemic deficiencies,” there was growing distrust of police and a loss of confidence in the criminal justice system.

The Davis family has certainly lost confidence.

Baltimore police first arrested Keith Davis in June 2015. They alleged that he tried to rob a taxi driver and then fled on foot. Davis said he saw police running toward him, so he ran, too, because he was afraid. He has always maintained he was a victim of mistaken identity.

In an attempt to apprehend Davis, police fired 44 shots, three of which hit Davis and left him unconscious, according to a police report.

At the October 2015 trial on the robbery charge, the taxi driver testified that Davis did not look like the person who had tried to rob him.

Francis-Williams could not pin the officers down on who had been the first to reach Davis after the shooting. Two different officers claimed to have been the first on the scene; two different officers said they had been the one to handcuff Davis.

A jury acquitted Davis on all but one charge — gun possession.

But Davis said he had no weapon on him. He testified that he thought police had planted the gun on him after he had been shot. That scenario may not be hard for many to believe in light of the Baltimore Public Defender’s Office releasing a video in July of a Baltimore police officer allegedly planting drugs at a crime scene.

Yet, after the robbery trial, Baltimore police and prosecutors alleged that the gun they found was tied to an earlier shooting. Kevin Jones, who worked as a security guard at Pimlico racetrack, was shot five hours before Davis was alleged to have robbed the taxi driver. Davis was charged with first-degree murder.

That trial, held in 2016, resulted in a hung jury — with 11 jurors voting for acquittal and one who couldn’t decide.

In a letter to the judge, a juror wrote: “The sole juror holding out was of the impression that Mr. Davis’s counsel had to prove his innocence.” The juror said everyone then reread the judge’s instructions stating that it was the prosecution’s burden to prove a defendant’s guilt beyond a reasonable doubt. “But the rereading did not resonate with the single juror.”

Davis was retried on the murder charge in October. But this time, a week before the trial, prosecutors announced a surprise witness: the inmate.

David Gutierrez was convicted in 2007 of involvement in a criminal conspiracy to distribute drugs in Texas. He was serving a 25-year prison sentence. He had also been convicted of attempted murder and sentenced to seven years. And, according to a transcript of an interview police held with Gutierrez in preparation for his testimony, he saw snitching as “God providing opportunities to me.”

His account of Davis boasting about the killing made no sense, Francis-Williams said.

Davis had refused a plea deal that might have cut his sentence in half. He had a couple of previous convictions for assault and drug possession, but he had had no contact with police since 2012. He had been working for a food services contractor, and his employer had nothing but praise for his work and reliability.

There was a groundswell of community support for Davis, not to mention the support of his family, who visited at least once a week. Activists in Baltimore have rallied around the case.

The Davises are raising four children. One of them, a 10-year-old son, had come to court with a handwritten plea for mercy. “He wanted the judge to know that they visit their dad every week and that he helps them with homework,” Francis-Williams said. “He wrote about missing the pillow fights where dad and the children would gang up on mom.”

Keith Davis remains behind bars as he faces a fourth trial since being arrested for the robbery. He has been held without bond each time. Each trial had been its own Exhibit A in an indictment of how poorly a criminal justice system operates.

For now, Kelly Davis is less focused on the larger problems of the system. She is working to get the charges against her husband dropped. And also on how to manage her children’s expectations.

“They are decorating the Christmas tree with pictures of him,” she said. “They’re hoping that Santa Claus will see the photos and bring their father home.”