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Bloodlines: The Death of Chicago Dermatologist David Cornbleet

After dermatologist David Cornbleet was murdered in his Michigan Avenue office, his son, Jonathan, devoted himself to finding the killer. Now a shy and troubled young man—a former patient of Dr. Cornbleet’s—has confessed. But that man’s anguished father is arguing that a drug prescribed by the slain doctor may have contributed to the killing.

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Surveillance footage from around the time of the murder showed a man police later identified as Hans Peterson hiding his face behind a bloody garment as he left the building.


This is a story of fathers and sons, grief and blame, obsession and determination, sickness and murder—and, above all, of differing perceptions of justice.

To the public, the murder a little over a year ago of David Cornbleet, a Michigan Avenue dermatologist with an old-fashioned practice, began as an unnerving mystery, one of those disturbingly brutal crimes charged with tantalizing clues and lurid intrigue.

Who would kill the kindly doctor who seemingly had no enemies? Why would the killer carry out the crime in such a viciously personal way—by stabbing him over and over and beating him so badly that, in the words of Jon Cornbleet, “my own family was not allowed to see him in his casket when we buried him"? Who was the mysterious young man caught on the building’s security cameras shortly before and after the murder?

The mystery apparently was solved in August when Hans Peterson turned himself in on the French Caribbean island of St. Martin and reportedly confessed. Suddenly, the narrative changed from a murder mystery to a tale of good versus evil. “The Look of Hate,” the Chicago Sun-Times declared in bold black lettering above a full-page mug shot of Hans Peterson. And, indeed, with his flat stare, shaved head, and chin shrouded in dark stubble, the accused man exuded menace.

Despite the reported confession, he was fighting extradition. His mother, it turned out, was French, which entitled him to declare himself a national. France declared its sovereignty in the matter, and a French judge ruled that a 1927 national law prohibited Peterson’s return to Illinois.

That, in turn, touched off a campaign by the Cornbleet family—led by the son—to pressure France into relinquishing the man who the Cornbleets say is a lifelong U.S. citizen with few ties to France. Among those supporting the effort are Mayor Daley and both U.S. senators from Illinois—Barack Obama and Dick Durbin. The U.S. State Department has weighed in on the side of extradition.

But as tenacious as Jon Cornbleet has been in pursuing justice for his father, Tom Peterson has emerged as equally dogged in arguing that his son—and the entire Peterson family—are also victims. The father claims that the controversial acne medicine Accutane, prescribed to his son more than five years ago by the murdered doctor, turned Hans Peterson psychotic, a condition that possibly made the young man violent enough to kill.

In blog comments he first posted in 2002, Hans Peterson claimed the drug gave him severe headaches and bowel problems, caused his hair to fall out, and destroyed both his libido and his ability to enjoy sexual pleasure. In short, he wrote, the drug had ruined his life—an outcome that he blamed on the “unethical” dermatologist who had prescribed it.

Cornbleet’s children say that blaming the drug for the murder is preposterous and an insult to their father. “This whole Accutane thing is a front,” says Jonathan Cornbleet. “Hans Peterson—the only patient in my father’s 28-year history who thought Accutane did him in—is a coward who is trying to blame a drug for a terrible crime.” The son says his father saw Peterson only once, and Peterson took only two doses before stopping the medication. How, the Cornbleets ask, could such a small amount, taken four years earlier, make someone crazy enough to kill—and not just kill, but devise and execute a highly complex plan with the clear aim of getting away with it?

Even Hans Peterson’s father acknowledges that it sounds “hard to swallow"—until, he adds, you look more closely at the long and checkered history of Accutane. The drug has been associated with birth defects and numerous physical problems, as well as with psychiatric disorders, including psychosis and aggressive or violent behavior.

Tom Peterson has publicly expressed his condolences to the Cornbleets. But he also has been highly critical of the dermatologist, calling him “one of the villains” as well as “one of the victims.” He asserts that Dr. Cornbleet inappropriately prescribed Accutane to Hans, given that the young man had only a mild case of acne. Tom Peterson bases the claim on—among other things—the drug’s package insert warning, which states: “Accutane should be reserved for patients with severe nodular acne who are unresponsive to conventional therapy, including systemic antibiotics.” The father also says the dermatologist failed to ask Hans about his psychiatric history, which included bouts of depression. Though no consent form is required, such screening is recommended in the package warning. Finally, Tom Peterson claims that the dermatologist gave Hans improper instructions on how to take the medication, which led Hans to take damagingly powerful dosages.

Dr. Charles Zugerman, an associate professor of clinical dermatology at Northwestern University’s Feinberg School of Medicine, says he doubts the link between psychiatric disorders and Accutane. Still, he screens his patients for depression and has them sign a consent form outlining potential side effects, such as depression, irritability, and suicidal thoughts. If a patient has a history of mental health issues, he requires that the patient bring a letter from a psychiatrist saying it’s OK to prescribe Accutane. Zugerman also says he prescribes Accutane as a “last line of defense” and only for the most serious cases of acne. “It’s not for mild acne,” he says. “I’ve never used it as a first-line drug, nor should it be.”

What went on during that first visit between Hans Peterson and Dr. Cornbleet may never be known. The only account extant is Peterson’s. The Cornbleet family say their father was diligent, responsible, and cautious. They point out that he had never been sued, nor had he faced any sort of professional discipline. “My father was a great doctor and a great man,” says Jon Cornbleet.

Hans’s father doesn’t disagree. But he does believe that the drug caused a drastic and devastating change in his son: “Before, he was somebody you could sit down with, look in the eye and communicate with,” Tom Peterson says. “Afterwards, that was gone, and it’s remained gone and I believe it will be gone forever.”

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Photograph: Courtesy of Jonathan Cornbleet


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