Knox's disputed diagnoses could mean Dakota Black, Josh Gehde are innocent

Nearly nine years after her son, Brayden, died, Shannon Turnbill still replays the image of the 5-year-old lying on the bed, unresponsive.

“It’s a picture I’ll never get out of my head,” she said of the encounter in October 2013. “His eyes were rolled back. It almost looked like he was having a seizure but not moving.”

After a University of Wisconsin doctor trained in identifying child abuse said Brayden had suffered from abusive head trauma, law enforcement blamed the only adult home with Brayden: Turnbill’s boyfriend, Dakota Black of Sun Prairie, Wisconsin.

In April 2016, Josh Gehde found his girlfriend’s 2-year-old daughter lying lifeless on the floor of their Madison, Wisconsin, apartment. Just minutes before, Gehde had given the toddler crackers and went to the bathroom to shave. When he came out, he saw chewed-up crackers on the rug near her face. He turned over her already cold body, struck her back to dislodge food and called 9-1-1.

The girl died two days later after being removed from life support. Dr. Barbara Knox, the same UW child abuse pediatrician from Black’s case — who has been suspended and investigated by two hospitals in two states — said abusive head trauma caused the brain injuries that killed the girl.

Courts, legal experts and medical specialists are increasingly scrutinizing the abusive head trauma diagnosis, an umbrella term that includes the controversial diagnosis of shaken baby syndrome, for lacking a scientific basis and criteria for diagnosis.

In both cases, Knox said the injuries happened within minutes of the child’s collapse, blaming the last person with the child. She testified in both cases to a “reasonable degree of medical certainty” that each child died from abuse. The defense’s experts blamed other possible causes and conditions, saying they saw no signs of abuse.

“It would be most unusual to have a fatal head injury without an obvious large bruise on the scalp and a skull fracture,” Black’s expert, neuropathologist Dr. Jan Leestma, said in a report. “This child doesn’t have any of these things.”

But in the end, the juries in both cases believed Knox.

Black and Gehde are serving lengthy sentences in Wisconsin prisons, convicted of murdering the children in their care. They pleaded not guilty and refused prosecutors’ plea deals, despite facing decades behind bars. Both unsuccessfully appealed. Some family members of the children who died, including Turnbill, say they do not believe these men killed their children.

And Wisconsin Watch has identified at least eight cases in which Knox determined a child had suffered head trauma from abuse that investigators and medical specialists said were instead caused by benign medical conditions, injuries from severe birth trauma, accidental falls, a bleeding disorder and a possible stroke.

Knox did not respond to attempts to reach her for comment.

These controversies are not unique to Wisconsin. In late April, a Texas appeals court halted the execution of Melissa Lucio, convicted of killing her 2-year-old daughter in 2007— a death attributed to “blunt force trauma” to the head.

Lucio and other family members had told police the girl fell down the stairs and was not abused — but then Lucio confessed to killing her after five hours of interrogation. The high court, citing several factors including Lucio’s possible innocence, sent the case back to a lower court for review.

Nationally, since 1992, 26 people have been exonerated following convictions on charges stemming from diagnoses of abusive head trauma or shaken baby syndrome, according to The National Registry of Exonerations.

Critics say the diagnosis — which is accepted by the American Academy of Pediatrics — remains an untested hypothesis. Speaking on behalf of the academy, Dr. Suzanne Haney said in a statement to Wisconsin Watch that those who disagree with its position on abusive head trauma are “pseudo-experts and defense attorneys who have something to gain.”

Yet even one of the doctors who first proposed the hypothesis decades ago pleaded with the medical community to stop using it in the courtroom, stating “these are simply hypotheses, not proven medical or scientific facts.” In 2012, Dr. Norman Guthkelch called for independent research on brain and eye bleeding “by individuals who have no personal stake in the matter.”

Earlier this year, a New Jersey judge labeled abusive head trauma “junk science” and refused to allow testimony about the diagnosis in his courtroom. Summing up five days of expert testimony, New Jersey Superior Court Judge Pedro J. Jimenez concluded: “What the literature and testimony have clearly shown is that AHT is an assumption packaged as a medical diagnosis, unsupported by any medical or scientific testing.”

The Wisconsin Legislature mandated tracking shaken baby syndrome in 2005, recording over 2,000 allegations since then. But only 40% have been substantiated, according to reports obtained online and through an open records request.

Keith Findley, co-founder of the Wisconsin Innocence Project, has been challenging the use of the diagnosis in the courtroom for over a decade. Findley questions even the “substantiated” cases.

“This notion of ‘substantiated’ really disguises all of the ambiguity, the uncertainty and the error that’s inherent in this whole system,” he said. “So I would never accept, at face value, their cohort of cases as truly cases involving abuse.”

In recent years, a growing body of research has revealed that a broad range of illnesses, genetic conditions, natural causes, birth trauma and accidents can cause the same brain and eye symptoms. Biomechanical modeling using dummy dolls has failed to show an adult could cause those symptoms by shaking.

And in over a dozen videotaped incidents where adults were caught abusively shaking children, the child did not suffer from the symptoms associated with abusive head trauma — and some of them were not injured at all.

During her 13-year tenure in Wisconsin, Knox acted as a crucial liaison between the UW’s Child Protection Program and law enforcement, providing medical diagnoses, consultations or expert testimony in over 200 criminal cases, according to open records responses from 14 district attorneys in southern and central Wisconsin and an analysis of electronic court records by Court Data Technologies.

Knox led the UW program until 2019, leaving after the hospital investigated whether she bullied her colleagues. Alaska CARES hired her that same year to lead the state’s forensic child abuse clinic. A joint investigation by Wisconsin Watch and the Anchorage Daily News found Knox generated similar allegations there.

During her brief tenure, the entire medical staff of Alaska CARES left or had their jobs reassigned. Knox submitted her resignation from Alaska CARES in January, scheduled to take effect on April 1. In March, online records show Knox was issued a medical license in Florida.

Dodge County District Attorney Kurt Klomberg said he stopped using Knox as an expert in 2017 after she failed to provide a timely report in an abusive head trauma case.

“I seek to engage medical experts who I can rely upon,” Klomberg said. “I determined that I would not likely support a case involving Dr. Knox’s independent opinion several years ago.”

Of the 208 cases found by Wisconsin Watch, the Dane County District Attorney’s Office brought 124, over 70% of them since Ismael Ozanne’s election in 2010.

In an interview, Ozanne expressed confidence in convictions made by his office involving Knox’s diagnoses.

“We were not just speaking with Dr. Knox alone,” Ozanne told Wisconsin Watch. “We were having to reach out to other experts . . . And, to my knowledge, none of those diagnoses were ever called into question.”

Ozanne said he has not contacted UW to discuss possible misdiagnosis, adding, “I would assume if there were questions, they would reach out to us.”

Findley said the fact other doctors agreed with Knox “does not resolve the matter” because of the “repeated allegations and findings that Dr. Knox bullied colleagues” and that “plenty of other doctors and experts have raised concerns about some of her determinations.”

He added that Knox’s work history “ought at the very least prompt serious concerns about what wreckage she might have left in her wake in this jurisdiction.”

The day Brayden Turnbill collapsed, four people who saw him after school told Sun Prairie police they noticed something off with the normally cheerful, fun-loving kindergartner. Two, who were children, described Brayden as looking “sad,” and as if he had been “crying without tears.”

Black said he repeatedly asked Brayden if he was OK after he came home from school with “bloodshot” eyes and acting “whiny.” Patricia Garwo, Turnbill’s cousin who picked Brayden and her children up from the bus that day, also asked him several times if he was alright, according to police reports.

The boy’s 5-year-old cousin told police that she twice saw Brayden fall from the monkey bars on the school playground. But the jurors never heard the girl’s testimony. Dane County Circuit Judge Stephen Ehlke barred details of the reported falls, ruling it irrelevant since she did not see Brayden hit his head.

After questioning Black at home for hours, police arrested him on an outstanding probation violation for a drug charge and took him to the Sun Prairie Police Department.

Detective Frank Smith told Black he believed everything Knox told police — the boy’s collapse from a massive brain injury happened within minutes of being abused, according to a transcript.

After Black denied harming Brayden — “I love that kid like he’s my own son” — the officer would have none of it.

“If I had any doubt or reserve of what she (Knox) told me, I wouldn’t be accusing you of doing this,” Smith said. “But I am because I believe her. I have that much faith in her science and her training.”

Ehlke’s ruling barring the testimony about falls on the playground kept defense experts from discussing how short falls can sometimes cause serious brain injuries in children, and in rare cases, death. In 12 of the 18 cases cited in that study, the children experienced a “lucid interval” of as long as two days before collapsing.

Black was convicted after a nine-day trial in Dane County Circuit Court. Turnbill refused to testify for the prosecution. “I still believe that something happened to him at school,” she said.

Black, now 32, won’t get out of prison until 2045.

Black and Turnbill’s two sons, who are now 9 and 8, know their father is in prison because of something that happened to their brother, but she has spared them the details.

She tells them, “The police don’t always tell the truth . . . the lawyers, the judges; the news doesn’t always tell you the truth.”

Turnbill hopes in sharing her story she can uncover the truth of what happened to her son that day — and find some justice for Black.

“Someday, I hope they figure out what really happened, and let him go.”

‘I’m not going to admit to something I didn’t do’

The day the girl collapsed, Joshua Gehde had lived with his girlfriend and her daughter for six months. “It felt like we were becoming a family, like everything was coming into place,” Gehde said during a phone interview from Stanley Correctional Institution.

A firefighter reported using forceps to remove regurgitated food from her airway. A police officer who arrived on the scene originally concluded the event was a “tragic accident,” according to court documents.

Two days later, the girl died at the UW. Doctors reported the girl had brain and eye bleeding and brain swelling. Citing the brain and eye findings as a “constellation” of injuries — and marks elsewhere on her body that Knox labeled as bruises — the doctor declared the girl suffered “definite abusive head trauma.”

At the request of Madison police detectives, Gehde reenacted how he gave her back blows to dislodge the food from her throat on a toddler-sized mannequin. Detectives rejected his story based on what Knox told them. Said Gehde, dissolving into tears: “I’m not going to admit to something I didn’t do. I loved that girl.”

Three medical specialists hired by the defense testified the girl died after blood clots in her brain caused a seizure, starving her brain and heart of oxygen. A neuroradiologist said small seizures can mimic a choking incident. And the girl’s autopsy report revealed she had bitten her tongue, a common occurrence in children having seizures.

In her medical report, Knox acknowledged the girl’s brain scan showed blood clots and bleeding throughout her brain, but, coupled with the child’s multiple bruises, concluded the brain injury was due to abusive head trauma.

The girl’s mother did not respond to interview requests, and attempts to interview other family members were unsuccessful. However, private messages shared with Wisconsin Watch between the Gehde family and some of the girl’s family members as recently as 2020 revealed they believed Gehde is innocent.

Gehde’s 20-year prison sentence ends in 2039.

“My whole life was stripped from me,” Gehde wrote in an email, “for something I didn’t do.”