Excerpts from the diary of 16-year-old Pauline Parker of Christchurch, New Zealand, 1954:

February 13th: Why could not mother die? Dozens of people, thousands of people are dying every day. So why not mother, and father too? Life is hard.
April 25th: Deborah [her 15-year-old friend Juliet Hulme] and I are sticking to one thing. We sink or swim together.
April 28th: Anger against mother boiled up inside me. It is she who is one of the main obstacles in my path. Suddenly a means of ridding myself of the obstacle occurred to me. If she were to die …
April 29th: I did not tell Deborah of my plans for removing mother. The last fate I wish to meet is one in a Borstal. I am trying to think of some way. I want it to appear either a natural or an accidental death.
June 6: We are both stark, staring mad.
June 19th: We practically finished our books today and our main “ike” for the day was to moider mother. This notion is not a new one, but this time it is a definite plan which we intend to carry out. We have worked it out carefully and are both thrilled by the idea. Naturally we feel a trifle nervous, but the pleasure of anticipation is great.
June 20th: We discussed our plans for moidering mother and made them a little clearer. Peculiarly enough, I have no qualms of conscience (or is it peculiar we are so mad?).
June 21st: I rose early and helped mother vigorously this morning. Deborah rang and we decided to use a brick in a stocking rather than a sand-bag. We discussed the moider fully. I feel keyed up as if I was planning a surprise party. Mother has fallen in with everything beautifully and the happy event is to take place tomorrow afternoon. So next time I write in the diary mother will be dead. How odd, yet how pleasing.

On the afternoon of June 22, Parker and Hulme ran into a Christchurch tea shop, crying that Parker’s mother had tripped on a plank and hit her head on a brick. “Mummy’s been hurt terribly,” Parker said. “I think she’s dead.” Police found the body of 45-year-old Honora Mary Parker on a secluded path in nearby Victoria Park. An autopsy found “forty-five discernible injuries, twenty-four being lacerated wounds on the face and head.” Parker quickly confessed under questioning:

Q: Who assaulted your mother?
A: I did.
Q: Why?
A: If you don’t mind I won’t answer that question.
Q: When did you make up your mind to kill your mother?
A: A few days ago …
Q: What did your mother say when you struck her?
A: I would rather not answer that.
Q: How often did you hit her?
A: I don’t know, but a great many times I imagine.

It transpired that Hulme’s father had planned to take Juliet to South Africa, and both girls knew that Mrs. Parker would refuse to let Pauline go with her. “These girls are not incurably insane,” the prosecutor told the jury. “They are incurably bad.” They were sentenced to five years in separate prisons.

Ludwig Schlekat bought a bank with its own money. Over the course of 17 years, starting in 1936, he embezzled $600,000 from the Parnassus National Bank of New Kensington, Pa. Then he invented two fictional investors and arranged for them to buy the bank and make him president.

In his new position he earned $800 a month, four times the salary he’d been getting as a teller. He bought a $19,500 home, $13,000 in furnishings, and a $1,000 diamond for his wife. When regulators pounced on these he resisted, saying they’d been bought with earned rather than stolen money. He went to jail for 10 years.

In June 1946, 44-year-old Fern Bowden filed for divorce from her husband James, charging him with “cruel and inhuman treatment” and asking $100 a month to support their two teenage daughters. James filed an answer denying the charges and accusing his wife of keeping company with other men while he had been in Alaska on war business.

In mid-July, James began working with a small trunk which he kept locked in the basement of their Oregon home. He refused to tell the family what it contained but warned them repeatedly not to try to open it; when the girls came upon their father working on it he shouted at them to get out. Only he and their mother, he said, had the padlock combination.

On July 27, alone at home, Fern opened the box. “The cellar of the Bowden residence was wrecked by the explosion,” reported the Associated Press. “Small pieces of flesh and bone found scattered throughout the shattered parts of the home have been identified by the police criminal laboratory as human.”

Detectives determined that the trunk had contained six sticks of dynamite rigged with tacks, wire, and a small battery.

James was charged with illegal possession of explosives and first-degree murder.

On June 23, 1908, a messenger delivered a bottle of ale to the door of Philadelphia doctor William Wilson. “We are taking the liberty of sending a few physician’s samples of our new product,” read an accompanying letter, which bore the name of a well-known Philadelphia brewing company. “As the beneficial qualities of our ale is to be our strong talking point, we have decided to cooperate with physicians as far as possible in the introduction of our goods.” It asked him to sample the product and to respond if he felt he could recommend it to his patients.

Three days later, Wilson sampled the bottle. Within 30 minutes he was dead of cyanide poisoning.

On June 29, coroner Rush Jermon received a typewritten letter:

Dear Mr. Coroner:

I want to write you regarding the death of Dr. W.H. Wilson.

In some way he induced my wife to become a patient of his. As a result of poisonous injections he used, she died a few weeks ago. In order to protect her name, I did not give the last attending physician all the facts, and she was buried with another cause assigned.

To rid the community of this wholesale killer, I have removed him like a weed from a garden. …

Now that this service to the community is rendered and the death of my dear wife avenged, I am going to quit this part of the world. I don’t think you will ever find me but I don’t care much what happens anyhow.

My only regret is the grief caused his wife and child but I believe they are better off without him. I say let those who live by poison die by poison.

“By the time you get this on Monday morning, I will be far from here,” it concluded. It was signed “An outraged husband and father.”

An investigation showed that the killer must have mailed the first letter from a West Philadelphia postal station at 1 a.m. on June 23, but no one remembered seeing him there. A clerk at the messenger service described a clean-shaven, neatly dressed man of about 40 wearing a black derby, and a station agent at Bristol, Pa., recalled a man of that description jumping briefly off a train to mail a letter on June 27, the day after Wilson had died. This man had apparently bought a ticket at Torresdale, a small station between Philadelphia and Bristol, earlier that day.

But there the trail ended. The mystery became a nationwide sensation, but no further progress was made. An inquest on July 10 returned a verdict of death by cyanide of potassium poisoning at the hands of a person or persons unknown. The killer was never found.