Determining whether a death is murder or natural often comes down to forensics. In New York City, a medical examiner and his assistant redefined how to do it. Author Deborah Blum, a Pulitzer Prize winner and professor of science journalism at the University of Wisconsin, wrote The Poisoner's Handbook about New York City’s chief medical examiner, Charles Norris, in 1920s New York, and PBS picked up the storyreleasing it earlier this year as a documentary.

Forensics in the early 20th century came down to removing the politics and putting science into pathology, forever changing how medical examiners process evidence. To help Norris in his work, he was assisted by Alexander Gettler, an expert toxicologist.

It was a daunting task. In the early 1920s, the average family medicine cabinet was a would-be poisoner's treasure trove of radioactive radium, thallium, and morphine included in everyday household products. Norris and Gettler had their work cut out for them.

So Norris began classifying death investigations according to the chemical detected in corpses by Gettler's toxicology tests. Intentional killers were able to cloak their crimes as natural or accidental deaths—that is, until Gettler and Norris perfected their work.

Blum's book follows their historic findings during the Prohibition era and the evidence the pair unearthed that pointed to murder—or not.

I sat down with Deborah Blum to talk about her book, poisons, and murder. Here is that interview:

Question: I know your father was a scientist. Is that what drew you into the field? And what was it like growing up with a scientist for a father? Did he encourage you to follow in his footsteps? 

Deborah Blum: Yeah, he was a huge influence. I think partly because he loved science—or in his case, bugs (he was an entomologist)—so much that he always brought it home. When he was interested in spider poisons, he brought home a black widow spider in a plexiglass case and kept it in the middle of the dining room table so he could watch it. He gave me a tarantula as a housewarming present when I got my first apartment in college. He also gave me a chemistry set for Christmas when I was eight years old. It was one of those wonderful old sets with all kinds of dangerous compounds in it. I remember I “borrowed” my mother’s perfume when I needed alcohol for an experiment and got in memorable trouble with her. And he really wanted me to be was a scientist—one of the great things about him was that he never doubted that my sisters and I (I’m the oldest of four) were capable and smart. He was thrilled when I started out in college planning to be a chemist. I might be today if I wasn’t such a klutz. They had to evacuate my freshman chemistry lab thanks to a poisonous cloud that I created one day. And, of course, I set my braids on fire in a Bunsen burner. I more or less drifted into writing out of self-preservation. My father was not happy about that change—he kept telling me that I could safely be a theorectical chemist. But he’s become a fan.

Is it tougher today to get away with murder by poison than it was in earlier decades, and if so, why?

Yes. The 19th century is sometimes called the golden age of poisoners because in the early 1800s, scientists had not figured out how to detect a single poison in a corpse. It wasn’t until the 1840s that the first test for arsenic became available. It wasn’t for another 30 years that chemists figured out to detect plant alkaloids (cyanide, nicotine, morphine) in a corpse. And poisons were easily available—arsenic was in everything from cosmetics to coloring agents to fly paper. And, just using arsenic again as an example, it’s a broad-spectrum poison that can mimic a natural illness. So you can see in this time period, where scientists are playing a catch-up game with killers, it was easy to get away with a poison murder. That really changed in the early 20th century when some very determined chemists came together to build the field of forensic toxicology—and started very publicly catching murderers.

Murder by poison sounds extremely painful. While murder in itself is cruel, is poison one of the most inhumane ways to kill someone?

I’ve always thought that poisoners are the coldest killers. Their murders are always premeditated—never by impulse. They have to pick the poison (they often research it in advance) and plan out how to use it to attack their victim. So they have a lot of time to think about how bad this is going to be. And then they watch as their victim drinks or eats the poison. There was a researcher in Pittsburgh who was recently charged with mixing cyanide into his wife’s energy drink. Among the evidence was a text he sent to her, urging her to drink it up, that had a smiley face. How creepy is that?

You have said that the goal of forensic science is much more than establishing criminal guilt and that forensics, if done right, can prove innocence. Have you seen cases where this has proved true?

In my book, The Poisoner’s Handbook, I tell the story of a man accused of a dismemberment murder. As it turned out, his neighbor had died from carbon monoxide poisoning due to a gas leak in his apartment. He also suffered from gas poisoning and hazily believing he’d killed her, he panicked and tried to dispose of the body by cutting it up and dropping the pieces in the river. Incredibly stupid, right? But not homicidal. The toxicologist in my book, Alexander Gettler, showed that she’d died of carbon monoxide poisoning before he cut her up. And that finding, plain and simple, saved him from the 1920s electric chair. Of course, he did deservedly go to prison for illegal dismemberment of a body. But that basic issue—that you want forensic chemists to be focused on finding the truth in the science, be it guilt or innocence, is essential to the integrity of criminal justice.

What’s the least detectable poison by forensics testing and the most easily detectable? And what’s the most popular poison for killers today, and why?

The least detectable poisons in a body are those that kill in the tiniest amounts—so that the levels are so low that it’s very difficult to pick them up. Until a few years ago, ricin was almost undetectable in living tissue—and even today the tests for it are extremely complicated. The easiest poisons to detect have very visible symptoms—carbon monoxide, for instance, sets off a chemical reaction in the blood that causes a strong pink flush to color the skin. Poisoners today, as always, use easy accessible poisons. Antifreeze (ethylene glycol) has figured in a whole range of murders. And more recently there’s been an increase in killings using prescription narcotics.

Are poisonous plants used in murder, or is it rare?

There was a fascinating murder in London a few years back in which a woman, discarded by her lover, actually went to India to get some particularly lethal seeds from a species of monkshood (devil’s helmet) that grows there. And there was a woman in Missouri who planted foxglove (which contains digitalis) in her garden and tried to kill her husband by putting it in salads. Both are now in prison. The real reason plant poisonings are rare is that so many of the plant alkaloids—the cyanides, strychnine, morphine, nicotine—have been synthesized. So people may use them but they use the laboratory version.

Have you found that some killers and attempted murderers think they can use certain poisons to get away with murder?

I think that most poisoners believe they’ll get away with it. Their faith in their own cleverness is one of the reasons, like the plotting that a good poisoning requires. The Pittsburgh researcher I mentioned charged the cyanide to his university credit card. He was that sure he wouldn’t be caught?

I’ve read about cases where victims were poisoned over spans of time. What are the signs and symptoms to look for when someone is unknowingly being poisoned?

It depends on the poison. Ethylene glycol, the compound in antifreeze, famously causes kidney damage so you end up with some of the symptoms of kidney disease. Arsenic will cause a range of symptoms, from gastroenteritis to respiratory problems, but eventually can cause extreme sensitivity to touch in hands and feet and even skin lesions. There was a woman in Wisconsin who suspected that her husband was trying to poison her and left a letter about that with a neighbor. And she did die of poisoning. Bottom line—if you suspect anything like this, the best way to take care of yourself, my very best advice, is to leave.

Are there differences between a killer who, say, uses a gun and one who uses poison?

Well, shootings are a lot more common and can be done in a fury of anger or fear. Poisoners— with their emphasis on research, on plotting, and their apparent belief that this is a game—approach murder differently. There’s a mistaken belief that most poisoners are women. In fact, if you look at the justice department statistics, about 60 percent of poisoners are male. But if you look at homicide by gun, it’s more like 90 percent male. And that seems to tell you that a greater number of poisoners are women than in other types of homicide.

Are murders by poison ever preventable?

Mostly because poisoners make mistakes. For instance, that woman who put foxglove leaves in a salad got the dose wrong. Her husband got sick but he didn’t die. Or sometimes would-be killers brag to their friends who then call the police. In that sense they’re not so different from other kinds of killers.

Finally, has the Poisoner’s Handbook, both the PBS film and your book, helped the general public to better understand the science of poisons?

I hope so. When I wrote the book, I had this idea that if I wove some of the science of poison through a story of murder and detection and Agatha Christie-era New York, I could show readers that this was both wonderfully wicked and fascinating chemistry. It’s one of my favorite parts of the story. And I thought American Experience did a great job of bringing all of that to life in the film. It was so much fun to watch.

About the Author

Cathy Scott

Cathy Scott is a true crime author, journalist and blogger based in Las Vegas and San Diego.

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