LoginThis doctor specializes in diagnosing child abuse. Some of her conclusions have been called into question.
This story was originally published by ProPublica. Co-published with APM Reports.
Photography by Sarahbeth Maney.
Reporting highlights
- A powerful doctor: Dr. Nancy Harper is a leading child abuse pediatrician based in Minnesota. She testifies in criminal trials across the Midwest, almost always for the prosecution.
- Casting doubt: Defense attorneys and judges have called Harper’s testimony into question. Two families have filed federal lawsuits against Harper.
- A new review: Prosecutors in Hennepin County said they are conducting a “final, thorough review” of one of Harper’s cases that will include an evaluation of the “medical conclusions.”
In court, Dr. Nancy Harper comes across as professional and authoritative. Often she begins her testimony by explaining her subspeciality: child abuse pediatrics, which focuses on the diagnosis and documentation of signs of child abuse. Her role, she often reminds judges and juries, is solely medical. Whether or not to remove a child from their home, terminate the parent’s rights or, in the most serious cases, charge a caregiver criminally is not up to her.
According to Harper’s testimony, she and her team at the Otto Bremer Trust Center for Safe and Healthy Children in Minneapolis handle about 700 cases of suspected abuse each year. She has testified that 10% to 20% of those wind up confirmed for physical abuse, although it is difficult to determine if these figures are accurate since child protection cases are not public.
When Harper, the center’s director, and her team diagnose abuse, parents and caregivers often struggle to challenge those opinions. By Harper’s own estimation, she’s never been wrong.
“I don’t think I’ve ever had a case where I thought it was abusive head trauma and the other specialist didn’t,” Harper testified in 2023, in the case of a day care provider charged with the death of a child in her care.
The defense attorney in the case pressed her: “Have you ever incorrectly diagnosed a child with abusive head trauma?”
“Not currently to my recollection,” she answered.
But in a handful of cases, judges and juries have found day care providers and parents not guilty of crimes after Harper has testified that abuse occurred, though a verdict cannot necessarily be interpreted as a repudiation of Harper or any other expert witness’ determinations or credibility.
Additionally, two federal lawsuits filed recently accuse Harper of ignoring or even concealing alternative explanations for children’s injuries. And, more broadly, medical and legal experts are increasingly questioning a leading child abuse diagnosis, shaken baby syndrome, which is also known as abusive head trauma.
Harper did not respond to requests for comment. She has yet to respond to either lawsuit. In past court testimony, Harper has said that both shaken baby syndrome and abusive head trauma are considered scientifically valid diagnoses by the mainstream medical community. Any controversy, she has said, exists primarily in the legal world rather than the medical one.
Kathleen Pakes, a former prosecutor who now specializes in the forensics of child abuse cases for the Office of the Wisconsin State Public Defender, said Harper’s claim of never making an incorrect diagnosis strains credulity.
“There is no other specialty in medicine that has zero error rate. None,” she said.
Below are four cases in which Harper concluded there was abuse but courts or juries determined otherwise.
On July 12, 2017, an 11-month-old boy named Gabriel Cooper collapsed in his high chair at the day care that Sylwia Pawlak-Reynolds operated in South Minneapolis. Paramedics took him to Hennepin County Medical Center, where he was declared brain dead a day later.
Harper reviewed Cooper’s medical records and wrote that “in the absence of a well-documented consistent severe accidental injury, non-accidental trauma or abusive head trauma remains the primary diagnostic consideration.” The child, she wrote, was essentially shaken to death. Before any criminal charges were filed, Pawlak-Reynolds boarded a plane for her native Poland to care for her ailing father, according to her attorney. In February 2018, prosecutors charged Pawlak-Reynolds with two counts of second-degree murder, citing Harper’s diagnosis.
According to her husband, Will Reynolds, they did not realize Pawlak-Reynolds was pregnant when she boarded her flight to Poland. She remained there to give birth to their third child, who is now 6, while Reynolds remained in Minnesota with their two older children, who are now 13 and 16. Reynolds said he and his wife have no confidence that she will get a fair trial, and that she fears she will lose custody of their youngest child if she reenters the country. The family has now been separated for eight years.
Early in the case, Pawlak-Reynolds’ attorneys obtained the same copy of Cooper’s hospital records that had been provided to Minneapolis police, which included the paramedics’ report. The document had been printed out at a significantly reduced scale, shrinking the text to the point that some fields were illegible. Two years later, they obtained a second copy, printed at normal size, which revealed a possible alternate explanation for the injuries: “Mom recalls (patient) did fall 2 days ago, striking the back of his head.”
“That was the sort of proverbial silver-bullet evidence that we’re always looking for in every case and usually never find,” said Brock Hunter, Pawlak-Reynolds’ lawyer.
Polish courts, including an appeals court, have denied extradition requests from the U.S. three times, and the country’s minister of justice has affirmed the rulings. The denials are particularly critical of Harper’s assessment. Polish forensic experts evaluated the case records and took note of a finding by a neurology expert hired by Pawlak-Reynolds, who wrote that Cooper carried a gene tied to a blood clotting disorder.
The ambulance report, the Polish judges wrote, “was concealed from the defense.”
“Then, after the fact was made public, it did not affect the actions of the American authorities in any way,” a Polish district court judge wrote in 2022.
The Hennepin County Medical Examiner’s Office certified Cooper’s manner of death as “undetermined” and the date and place of injury “unknown,” a tacit disagreement with Harper’s opinion that Cooper would have collapsed “shortly after infliction of the trauma.”
The Hennepin County Medical Examiner’s Office declined to comment.
Then in 2023, Hennepin County Attorney Mary Moriarty wrote to Pawlak-Reynolds’ attorneys after meeting with them: “We agree that to resolve the current impasse regarding Ms. Pawlak-Reynolds, the best course for all involved is to dismiss the pending charges without prejudice, and for her to return to the United States.”
But months later, Moriarty changed her mind.
In a statement to ProPublica, a spokesperson for the Hennepin County Attorney’s Office wrote that the office is completing a “final, thorough review” of the case that will include an evaluation of “concerns regarding the medical conclusions and the overall strength of the case.”
Gabriel’s parents, Joseph and Samantha Cooper, did not respond to requests for comment. In a television interview in June, they denied that Cooper struck the back of his head two days before his collapse. They said that they want justice for their son.
Pawlak-Reynolds declined to comment through her attorney. In late February, her husband filed a federal lawsuit against Harper that claims she “knowingly and intentionally falsified, modified and erased exculpatory information” from her evaluation of Cooper, and she diagnosed abusive head trauma to “promote her own personal, academic, reputational and financial needs.”
Harper has yet to respond to the lawsuit. A spokesperson for Hennepin Healthcare, which operates Hennepin County Medical Center, declined to comment on the case or the lawsuit.
“There is no oversight,” Reynolds said. “It’s the thing they’re most resistant against and the thing that is most necessary to stop this legacy of brutality, that results in kids being taken away from innocent caregivers and innocent caregivers going to prison.”
In August 2017, Kathryn Campbell called 911 after a 4-month-old girl at her day care seemed lethargic and was “breathing wrong.” First responders did not take the baby to the hospital, but her mother eventually did. At the hospital, MRI scans showed fluid in the baby’s brain and doctors noted small bruises.
Dr. Barbara Knox, a child abuse pediatrician then with the University of Wisconsin, told police it was “obvious child abuse.” The Dane County district attorney charged Campbell with physical abuse of a child. Campbell pleaded not guilty.
But before the 2021 trial, Knox left the University of Wisconsin after she was placed on leave for “unprofessional acts that may constitute retaliation” and intimidation of her own staff. A Wisconsin Watch investigation cast doubt on Knox’s judgment in several cases of alleged abuse.
Knox did not respond to the Wisconsin Watch series or to ProPublica’s requests for comment. After two families in Alaska sued her in 2022, alleging she had wrongly concluded their children had been abused, Knox wrote in an affidavit that she has no control over whether police and child protection services workers take children away from parents, that she did not “conspire” with police or anyone else on custody issues, and that she did not personally evaluate one of the children. The lawsuit was dismissed in 2024 after the families agreed to drop the matter.
Knox moved on to a job at the University of Florida. According to a spokesperson for the university, Knox resigned as a pediatrician with the Child Protective Team in late June, effective Aug. 15. He declined to comment on the circumstances.
At Campbell’s trial, Knox’s name was never mentioned. Instead, Harper stepped in as an expert witness. When Campbell heard Knox had been replaced, she was initially hopeful.
“I’m like, oh, great, new eyes,” Campbell said. “They’re going to look at it and go, ‘This is nuts, I don’t agree with this.’ And I definitely was wrong.”
Harper’s assessment affirmed Knox’s diagnosis of abuse. She told the jury that the bruises were likely caused by squeezing by an adult’s hand. A medical expert hired by Campbell’s defense argued that the child’s bleeding could not be precisely dated and that a preexisting medical condition could have caused it.
After just two hours of deliberation, the jury returned a not guilty verdict. Campbell said she is grateful to have the case concluded, though she said she is still haunted by the accusations against her.
“That was the hardest thing too, going home after this case was done, and being like, ‘Am I allowed to be alone with my children now?’” she said. “It’s all because of the quote-unquote experts not doing their due diligence and looking further into underlying issues that these kids could have.”
In a statement to ProPublica, Dane County District Attorney Ismael Ozanne expressed confidence in both Harper and Knox, saying “their testimony had been consistent with many different medical professionals and experts in their own areas of practice.”
“It is important to note that a not guilty verdict by lay jurors hardly invalidates the widespread acceptance of abusive head trauma as a diagnosis in the medical community nor would it cause us to have concerns about Dr. Harper’s qualifications or knowledge in the field,” he added. “Jurors are not bound to accept any expert testimony as accurate.”
In the winter of 2022, a 4-month-old boy began breathing abnormally at his day care in Mineral Point, Wisconsin. His parents took him to a hospital, where he died days later. A police investigation determined that his day care provider, Joanna Ford, left him and several other children alone in her home for over an hour while she went to a tattoo and piercing parlor.
Prosecutors used Harper as an expert witness in the case. After evaluating the child’s medical records, she concluded that his injuries were “clinically diagnostic of abusive head trauma,” or, put another way, Ford shook the baby violently. She was charged with first-degree reckless homicide. Ford pleaded not guilty.
Ford’s defense lawyers successfully petitioned the judge in the case for a hearing to determine whether Harper’s expert witness testimony would be scientifically valid and admissible at trial. In response to questions, Harper explained why the child’s symptoms — brain swelling, blood under his skull, damage to his eyes — pointed to abuse, and why, despite the controversy surrounding it, the diagnosis of abusive head trauma was scientifically sound. She also explained that, because the baby was not walking or crawling, the fact that none of his caregivers could explain his injuries indicated abuse.
“People should know what happened,” she testified.
On cross examination by Ford’s lawyers, Harper said she couldn’t say for certain what time the abuse would have occurred, exactly how Ford had injured the baby and that there are no “great biomechanical models” for shaken baby syndrome.
A little over a month later, Judge Lisa McDougal delivered a highly critical ruling that barred Harper from telling the jury that the child died as the result of “abusive head trauma, non-accidental injury, child abuse or murder.” She also took issue with the idea that a lack of explanation for injuries is indicative of abuse, calling it a “leap in logic.”
“Offering a conclusive opinion as to how an injury may have occurred crosses a line and does not fit within the dictionary definition of what diagnosis is,” McDougal said. The judge also said that Harper views herself as an advocate, and that that casts doubt on her “fidelity to the scientific validation of abusive head trauma diagnoses, especially when it is a close call.”
The murder charge was dismissed. For leaving the children alone, Ford pleaded guilty to the lesser charge of neglect of a child where the consequence is death. She is serving a 10-year prison sentence. Ford, through her attorney, declined a request for an interview. The Iowa County district attorney also declined to comment.
On Feb. 4, 2022, Paul and Sarah Marshall hosted a dinner for her parents and a family friend at their home in Hudson, Wisconsin. Afterward, their 7-week-old son, Fox, became fussy. Paul Marshall carried him into the mother-in-law unit on the lower level of the house, which was cool and dark, to try to calm him. He emerged minutes later in a panic, yelling that the baby spit up and stopped breathing.
Paramedics rushed Fox to Children’s Minnesota, a hospital about 25 minutes across the state border in St. Paul. Doctors ran tests, and a scan showed Fox had a skull fracture with fluid pooling on both sides of his brain. He died days later.
Harper examined Fox, as well as his twin sister, Liana, and found “skull fractures, likely rib fractures, metaphyseal fractures.”
“This constellation of findings in a nonambulatory infant is clinically diagnostic of inflicted injury or child physical abuse likely occurring on more than one occasion,” she wrote.
But the Marshalls said that wasn’t true. They told Harper that Sarah Marshall had experienced a difficult pregnancy with gestational diabetes and severe anemia, and that Liana had a vacuum-assisted delivery. Both twins had been to their regular pediatrician over health concerns. While Liana’s health improved, Fox’s had not.
A spokesperson for Children’s Minnesota declined to comment on the case.
Because he was the last person alone with Fox before he stopped breathing, Paul Marshall was charged with first-degree reckless homicide. He was also charged with physical abuse of a child for hurting Liana. Sarah Marshall said there was no evidence that her soft-spoken husband had hurt their children.
“The state wanted to cast me as a naive idiot,” she said. “I chose not to believe it because of the logic and facts in my face. I had no reason to believe the accusation.”
At Paul Marshall’s 2023 trial, his defense lawyer, Aaron Nelson, cross-examined the other doctors who treated or evaluated Fox and Liana, and was able to highlight points of medical disagreement. A doctor who tested Liana for genetic disorders said she could not rule out rickets as a possible cause of her bone fractures. A neuropathologist did not agree with Harper that Fox had a trauma-induced blood clotting disorder. By Harper’s own admission on cross-examination, determining the age of the skull fractures in children Fox and Liana’s age was difficult. Nelson called six of his own medical experts to suggest that the difficult birth or a vitamin deficiency could explain the twins’ injuries.
“How many people have to be wrong for Dr. Harper to be right?” Nelson said in closing arguments.
After an 11-day trial, the jury found Marshall not guilty.
In a statement to ProPublica, St. Croix County District Attorney Karl Anderson pointed out that Harper was not the only treating physician who was concerned that Fox and Liana had been abused.
“A not guilty verdict does not mean that the jury concluded that the children were not abused,” Anderson said. “Rather, it means that they did not conclude that the state proved that Paul Marshall caused the death, beyond a reasonable doubt.”
Six weeks after the trial, the family moved three hours away into a century-old farmhouse that is far from the community that they felt wrongfully villainized by.
One of the cruelest impacts of the abuse diagnosis, they said, came after it was clear that Fox would die and the hospital staff began making preparations for his organs to be donated. Sarah Marshall said she had hoped to someday hear her son’s heart beating in another child’s chest. Instead, a court order put a halt to the procedure.
“They were already treating him as evidence,” she said.
The experience of going from a grieving parent to an accused murderer, her husband said, has given the couple post-traumatic stress. Paul Marshall said he is grateful to be with his wife and children, but what he calls a “broken system” has left them unsure whether or not to have another baby or even be left alone with one of their daughters.
“You get pregnant. You go to all of your appointments. You voice all of your concerns. You do everything you’re supposed to do as a parent and your child still dies. And the state tells you it’s your fault,” Sarah Marshall said. “I don’t understand why I live in a world like that.”
Mariam Elba contributed research.
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This doctor specializes in diagnosing child abuse. Some of her conclusions have been called into question. is a post from Wisconsin Watch, a non-profit investigative news site covering Wisconsin since 2009. Please consider making a contribution to support our journalism.
