One of my college buddies was a prosecutor in Virginia, where the job comes with the mellifluous title of commonwealth’s attorney.

He was prosecuting a man in the 1996 murder of a church organist when he asked an informant if he expected help on federal charges in exchange for testifying about the defendant’s jailhouse confession.

“It’s your understanding that what you’re doing here today doesn’t have any impact on federal sentencing, is that right?” the prosecutor asked.

“Right,” the witness testified.

When an appeals court overturned the murder conviction in 2012, it cited that exchange as the reason. Three years later, the state reprimanded my friend for ignoring a federal rule that says witnesses in trouble always expect favor at sentencing if they help prosecutors.

Hold his story in your mind.

It’s reason enough to believe that when Michael Wachs, a retired Anne Arundel County judge presiding last month over his second mass shooting case, declared a mistrial, he was doing a huge favor for the prosecutor, Anne Colt Leitess.

The judge found that she had tainted the jury deciding the fate of Charles Robert Smith by repeatedly bringing up statements and questions that he had ruled out using.

Now she should do the right thing and withdraw before Smith goes on trial for the three Annapolis murders again in September.

It is exceptionally hard to hold a prosecutor accountable. Cases like my friend’s are rare. He resigned and gave up his law practice, accepting the rebuke by saying his actions were a mistake. He settled a lawsuit by the man he prosecuted.

“These things undermine the integrity of the entire judicial process,” said David Jaros, faculty director at the Center for Criminal Justice Reform at the University of Baltimore School of Law. “We don’t rely on mistrials to do that.”

When Assistant Public Defender Anne Stewart-Hill stood up in the Annapolis courthouse Feb. 26, she argued that Leitess was guilty of more than a slipup. The defense called it misconduct.

Smith, 45, is charged with the deadliest outburst of gun violence in Annapolis since a man killed five of my colleagues in 2018.

Smith claims he and his mother had a long-running dispute with his Hispanic neighbors in the tiny Paddington neighborhood, and that he was afraid when he confronted Mario Mireles Ruiz, 27, during an argument with his mother over parking.

Witnesses said the Army veteran retrieved his gun. By the time police arrived, Mireles Ruiz; his father, 55-year-old Nicolas Mireles; and a family friend, 24-year-old Christian Marlon Segovia Jr., were dead on the sidewalk.

Officers found Smith in his house, where they said he had used his rifle to fire into the crowd after someone broke his window.

Police and prosecutors argued that Smith was a racist who feuded so often with the Ruiz family that they feared for their safety. He was charged with murder and hate crimes.

In the routine tides of a trial, the prosecution and the defense sparred from the start.

They argued over Smith’s views on immigrants and the victims’ immigration status, over allegations of criminal gang ties and a gun spirited away after someone shot at Smith’s house.

They clashed over Smith’s discharge from the Army because of a stabbing and over a jailhouse phone call between the son and the mother.

Rather than let these points go after Wachs sided with the defense, Leitess repeatedly tried to bring them up in other ways, Stewart Hill argued.

“Your honor personally admonished Ms. Leitess to stop making, proposing leading questions,” Stewart-Hill said during her request for a mistrial. “And she continued to do so.”

The prosecutor told the judge that any mistakes were unintentional, then went on the offensive.

She accused Smith’s attorneys of trying to erase the image Smith created for jurors with profane, angry testimony.

“His behavior yesterday on the stand, I would suggest, is why they’re asking for a mistrial,” she said.

Wachs disagreed, ruling that Leitess screwed up so egregiously that it couldn’t be fixed by telling the jurors to ignore it.

“I don’t believe you’re intending to cause a mistrial. I don’t want you to think that,” the judge told the prosecutor. “But that doesn’t change for me what was said in front of the jury in a crucial part of the case.”

Frustrated by the ruling, Leitess asked an administrative judge to remove Wachs from the retrial.

Her request is sealed from public view, but Wachs described it in his decision.

“My reason for agreeing that a re-assignment of this case makes sense is due to the state’s portrait of me to the victims, their family members, the public and the State’s Attorney’s Office staff that the mistrial that was declared was completely my fault,” he wrote in an explanation quoted by the defense. “(Which I wholeheartedly disagree with.)”

If Wachs had allowed the trial to continue, a conviction seemed likely. So did an appeal.

Stewart-Hill’s arguments were an invitation for a higher court to overturn the conviction, with the potential for a scathing critique of Leitess — like the one that ended my friend’s career.

Leitess, appointed in 2013, is a good prosecutor.

She fell short in 2014, losing the case against a New Jersey police officer charged with killing a man in a road rage attack. Local police, angry with her decision to bring murder charges, helped vote her out of office for four years.

She won it back in 2018 and convicted the man who murdered five people in the Capital Gazette shooting, then convinced a jury to send him to prison rather than a psychiatric hospital.

As with all prosecutors, Leitess’ righteous indignation sometimes seems like anger.

But in declaring a mistrial, Wachs did the right thing. He gave Leitess a second chance to put a man who killed three people and wounded three others in jail.

She should take it, and with the integrity she’s demonstrated in the past, hand it to someone else.