A timeline of turmoil

Philly DA Larry Krasner’s uncertain future: How a routine case devolved into controversy

Philadelphia District Attorney Larry Krasner.
Philadelphia District Attorney Larry Krasner.Chris Rukan / Staff Illustration / Photography by The Inquirer
Published

Philadelphia District Attorney Larry Krasner’s office has been roiled by controversy in recent months after a federal judge said Krasner and one of his supervisors may have committed crimes while overseeing a post-conviction case.

It could be months — or longer — before it’s clear if federal prosecutors agree that Krasner should face charges including conspiracy and obstruction of justice.

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But the events that led to that striking conclusion from U.S. District Judge Paul S. Diamond were laid out in testimony that unfolded in his courtroom this summer, as well as in a 40-page memorandum he filed in the case in September.

Krasner has disputed Diamond’s findings, and said he plans to file an appeal of the judge’s ruling, which also barred Krasner and one of his supervisors, Matthew Stiegler, from participating in the underlying case.

Here’s a recap of how the situation evolved from a routine legal matter into a contentious saga that could lead to consequences for the city’s top prosecutor.

2009

Dennis Johnson is convicted

In 2009, Dennis Johnson was convicted of second-degree murder after a jury found that he fatally shot Kenyatta Smith two years earlier during a robbery outside a North Philadelphia convenience store.

The case was largely built on the testimony of eyewitnesses, whose credibility Johnson sought to dispute at trial. Even after being sentenced to life in prison, Johnson maintained he did not commit the crime.

He filed several unsuccessful appeals in Pennsylvania courts. Then, in 2015, he filed a petition seeking to overturn his conviction in federal court. The case landed in front of Diamond.

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2022

The case is assigned to Jaclyn Mason

Prosecutors opposed Johnson’s petition for years. But in 2022, they changed course when it was assigned to a new assistant district attorney: Jaclyn Mason.

Mason had only joined Krasner’s office a few months earlier, and Johnson’s case was her first in her new role in the federal litigation unit. Although she had extensive experience as a lawyer — working primarily on patent and trademark cases — she’d never before worked as a criminal litigator, and she said she received almost no training in the DA’s office before being asked to handle cases.

Her boss was Stiegler, who had a controversial history working for Krasner. Over the course of a few years, he’d joined and left the office twice. And in one of those stints, nearly everyone under his supervision requested a transfer. One prosecutor later told Diamond that Stiegler did “not have the best reputation” among his colleagues.

When it came time to decide how to handle Johnson’s petition, Mason said, Stiegler had already made up his mind. Although he’d done nothing to independently review Johnson’s claims, Mason said, Stiegler had conferred with Johnson’s attorneys — including the Pennsylvania Innocence Project and federal defenders — and decided his conviction should be reversed.

“Matt told me: ‘If it’s good enough for the Innocence Project, it’s good enough for me,’” Mason said later. “The decision to concede had been made, and then I was his pawn.”

Larry Krasner timeline clips.

Mason also acknowledged that she reviewed almost nothing before submitting and signing off on her brief recommending Johnson’s conviction be thrown out. But at that point, she said, she believed she had to follow her boss’ orders.

“I didn’t know anything enough to push back,” she later testified. “I’d been at the office for four months — I’d never done this kind of work before.”

Once Mason did actually draft the brief, she said, Stiegler offered edits, and all of them made it into the final document. Another supervisor, Nancy Winkelman, the onetime head of the Law Division, also made suggestions that were included in the final brief, Mason said.

Mason’s name, however, was the only one that ended up on the document.

May 2026

Discovery of errors

A federal magistrate, Judge Lynne A. Sitarski, eventually agreed that Johnson’s conviction should be overturned, based in part on the findings in Mason’s brief.

But Sitarski’s decision was not binding — the final call would fall to Diamond. And in May, rather than accepting Mason’s conclusions, he decided to schedule an evidentiary hearing to hear testimony and weigh the pieces of evidence before issuing a ruling.

As the hearing approached, Mason reached out to a group of supervisors in the law division to prepare: Katherine Ernst, Steven Wildberger, David Napiorski, and Peter Andrews. And Ernst said when she reviewed Mason’s brief, she discovered it contained “significant errors” — issues that, in her view, contradicted the notion that Johnson’s conviction should be overturned.

The supervisors decided they needed to try to withdraw the brief.

Larry Krasner timeline clips.

Asking a judge to do so — and admitting a document was filled with mistakes — is a significant step for a lawyer to take.

But Ernst said the office had no choice: Lawyers are duty-bound to be honest with courts, and there was no ethical way to proceed with a document containing such errors.

The supervisors first decided to break the news to Mason. And in a meeting, they said, they asked her to sign on to the withdrawal with them.

But Mason declined. She told the supervisors the situation was Stiegler’s fault — and that his downfall was “a long time coming.” The supervisors later said she didn’t offer more specifics, and that at that point, none of them knew the extent of Stiegler’s role in the brief’s preparation.

Mason, however, felt the supervisors were setting her up to take the fall. She decided to resign, and said in her resignation letter that Stiegler had “used me to further his personal agenda” — and that he should be forced to “submit and swear in an affidavit that he erred and that he was responsible for what was filed in this case.”

She said she was prepared to stay until the end of June to wrap up any outstanding obligations, but that Krasner’s chief of staff, Jennifer Lin, told her that wouldn’t be necessary. Mason’s email was cut off, she said, and her badge granting her access to the office was disabled.

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Early June 2026

Mason resigns, and Stiegler tries to assign blame to her

After Mason resigned, her former supervisors began drafting the motion to withdraw her brief.

Stiegler, meanwhile, took on a different assignment: Seeking to blame Mason for the errors.

According to Ernst, in the days after Mason quit, Stiegler told colleagues she must have “purposefully inserted false facts” into her brief, and that it was “100% her fault and 0% his fault.”

And he came up with a plan to try to support that narrative, proposing that her colleagues review all of her work to find other cases with errors, so that the office could file a brief with Diamond casting Mason as “an ADA who went rogue, basically.”

The supervisors said no. Beyond viewing the proposal as inappropriate, Ernst said, she also pointed out to Stiegler that it would not help his reputation to show the court that one of his employees made consistent mistakes.

But Stiegler persisted — and even proposed the idea to Krasner.

And during a meeting on June 5, during which the supervisors were seeking Krasner’s approval on the motion to withdraw Mason’s brief, the DA repeated Stiegler’s proposal, describing it as “a really good idea.”

The supervisors again said no. Wildberger told Diamond he found the notion “tremendously inappropriate.”

Diamond, in his September memorandum, said it was more serious than that.

“In urging that others lie to me,” he wrote, “Stiegler might be liable for obstruction of justice.”

He also said Stiegler’s testimony about the episode contained enough omissions and “falsehoods” that it “may well amount to perjury.”

And he said Krasner’s attempt to work with Stiegler and urge others to present a false narrative to Diamond “might amount to criminal conspiracy.”

In the same June 5 meeting, meanwhile, Krasner did approve the supervisors’ motion to withdraw Mason’s brief, which they filed that afternoon.

But another dispute emerged — one that would linger well beyond that meeting.

Late June 2026

A potential conflict of interest

In Ernst’s view, the internal turmoil over the case — particularly the attempts to assign blame about what happened — had compromised the office’s ability to handle Johnson’s petition appropriately.

The internal discussions had become consumed by the office’s inner-workings, Ernst said, and not the merits of Johnson’s appeal, creating, in her view, a conflict of interest.

As a result, Ernst said, she told Krasner the case should be referred to the state attorney general’s office, the typical process if the DA’s Office has a conflict.

But Krasner disagreed.

In the supervisors’ telling, Krasner was consistently and sometimes angrily opposed to sending the case to state prosecutors. During meetings over the next several weeks, the supervisors said, Krasner repeatedly expressed disdain for the people who worked there, describing them as “Nazis” and saying he “hated” them.

The views are not new; Krasner, during his first week in office in 2018, fired 31 prosecutors, some of whom went on to join the attorney general’s office. And in 2019, Krasner said some people in his office had jokingly come to describe the AG’s Office as “Paraguay,” a South American country where Nazis took refuge after World War II.

Larry Krasner timeline clips.

Beyond the war criminal reference, however, the supervisors said Krasner expressed other reasons for opposing the referral.

One was that he wanted his staff to “protect the office,” the supervisors said. And according to Ernst, Krasner said: “We need somebody in the room so that [we] can control the proceedings.”

Ernst said she pushed back, telling Krasner: “A person can’t both protect the office and competently handle this case.”

But Krasner was insistent, they said. And he told them he was consulting with legal ethics experts — whom he did not name — to ensure there was no issue with keeping the case in-house.

Over the next several weeks, the supervisors said, they began putting their thoughts in writing. That practice led to additional disputes on June 24.

That day, according to Napiorski, he emailed Krasner a draft memorandum outlining the various issues the supervisors believed created a conflict. Napiorski said he emailed it to Krasner’s personal and work e-mail addresses because Krasner rarely responds to messages from his government account.

Two hours later, the supervisors said, an email response came from Lin, Krasner’s chief of staff. But the message opened by saying that Krasner had written it, and that he took issue with many of the assertions in the group’s memo.

In a meeting that afternoon, the supervisors said, Krasner also said he was angry that the supervisors had sent the memo by email because doing so created a record that could be discoverable in potential litigation.

The next day, Napiorski said, he spoke with his own ethics expert, who agreed that the case should be referred to another office. As a result, he said, he and Wildberger brought Krasner another new piece of writing: A draft of a letter that would refer the case to state prosecutors.

Krasner was “apoplectic,” Wildberger said. And he went on to threaten “consequences” for anyone who told Diamond about the conflict discussions — a reference that both Wildberger and Napiorski took to mean losing their jobs.

The two men called Ernst, who said the threat made it clear: They needed to recuse themselves from the case.

Ernst and Wildberger filed a memo before Diamond withdrawing their appearances that day. Napiorski and Andrews followed suit a day later.

Diamond, meanwhile, said in his September memo that Krasner’s threat to fire people who were seeking to tell the truth in court “could amount to obstruction of justice.”

July 2026

Examining attorney conduct

On July 17, Diamond held an evidentiary hearing in the case — which he decided to limit to issues concerning attorney conduct, rather than the merits of Johnson’s petition. He said he would address that later.

Mason took the stand first, describing what she viewed as an attempt to scapegoat her on Stiegler’s behalf. She also accused the law division supervisors of urging her to lie to Diamond — something the supervisors would later deny.

Stiegler also testified, saying he believed Mason had — and should have — conducted a full investigation into Johnson’s claims before filing her brief.

Behind the scenes, meanwhile, turmoil was continuing in the office.

On July 20, Wildberger stepped down from his supervisory role in the law division, later saying he did so because he had “lost faith in the administration of the Philadelphia District Attorney’s Office.”

And after Mason accused the supervisors of wrongdoing from the stand, Ernst and Wildberger filed a more detailed memo with Diamond about why they had stepped off the case, including by saying that Krasner had asked them to “protect the office” and potentially violate their ethical oaths.

Larry Krasner timeline clips.

Three days later, Krasner responded with a filing of his own, saying Ernst and Wildberger’s assertions were both unauthorized and “ill-informed.”

And although he did not — and has not — denied saying he wanted to “protect the office,” he said in a later filing that he “plainly did not appreciate [his subordinates’] repeated, unsolicited, and wavering advice” to refer the case to state prosecutors, and that their recommendation was “inexpert and legally unsupported.”

He also said he’d hired an expert who agreed with him — Bruce Green, a professor at Fordham Law School — and later attached a memo written by Green to one of his filings. Diamond would go on to call Green’s memo “a disorganized mess and largely useless.”

In addition, Krasner said, as a measure of extreme caution and to ward off any suggestion of a potential conflict, he hired an outside attorney to handle the case on his office’s behalf: Jean Peters-Baker, a longtime prosecutor from Missouri who previously led the prosecutor’s office in the county that includes Kansas City.

Diamond later disqualified her, saying that because Krasner had been hampered by the conflict issues months before he reached out to Peters-Baker, his decision to bring her aboard was invalid.

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September 2026

‘Often contradictory, evasive, or outright dishonest.’

All of the law division supervisors went on to testify before Diamond, and he said in his Sept. 16 memorandum that he found their testimony, as well as Mason’s, “compelling and corroborated by contemporaneous documents.”

Although Mason had accused her supervisors of encouraging her to lie in court, Diamond found that they hadn’t done so, saying they’d sought to truthfully tell him about the issues in her brief, and that her “understandable dismay caused her to misunderstand” their intentions.

The judge took a dimmer view of Stiegler, calling his testimony “often contradictory, evasive, or outright dishonest.”

Larry Krasner timeline clips.

And although Diamond did not call Krasner to testify about the saga, he nonetheless criticized the DA in his memorandum for not taking the stand, saying Krasner “chose” not to testify, and noting he didn’t submit an affidavit to offer his version of events.

Diamond’s decision to alert federal prosecutors about the case, and say they should investigate potential crimes by Krasner and Stiegler, was practically unheard of, legal experts said. The U.S. Attorney’s Office has declined to comment, and any investigation it might pursue would likely take months.

Johnson’s petition, meanwhile, remains in limbo. Diamond said the district attorney’s office could continue to litigate it — but with Krasner, Stiegler, and the law divisions’ supervisors removed from the case, it was not clear who might do so.

Staff Contributors

  • Design: Chris Rukan
  • Editing: Nancy Phillips and Julie Busby
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