In the little town of Villisca, Iowa, 35-year-old Joe Moore, his wife, his four children, and two visiting daughters of a neighbor went to bed on June 9, 1912.

The following morning, all eight were dead.

“The parties were all killed with an axe which was found in the house, the axe belonging to Mr. Moore,” reported Iowa attorney general Horace Havner. “The window shades were all drawn and the doors covered with clothing so that no light could get out from the house. The mirrors in the house were also all covered. Not one of the parties received any injury below the neck but the heads of the victims were all beaten to a pulp, the head of Mr. Moore being mangled worse than the rest, although they were all beaten beyond the possibility of recognition.”

Ten years of investigations, grand juries, trials, and arguments produced no convictions. The case remains unsolved.

See Hinterkaifeck.

In 1867, a Boston family paid its servant Bridget McDonald $38 in bank bills. A Martin O’Malley “asked her to let him take the money and count it, she not being able to read or write.” When she obliged, he refused to return the bills and threatened to burn them unless she opened the door. She did, and he went off with the money.

O’Malley was prosecuted for larceny, but the trial court seemed to feel that he was actually guilty of embezzlement, since he hadn’t taken the money from Bridget but merely kept it against her will. So it acquitted him.

A jury then convicted O’Malley of embezzlement, but he appealed — claiming that the act amounted to larceny. And apparently he went free.

(To prevent such injustices, many legislatures eventually combined larceny, embezzlement, and false pretenses into a single offense called theft.)

On Aug. 24, 1867, solicitor’s clerk Frederick Baker took a tea break and strolled into the meadows near the hop fields of Alton in Hampshire. There he found three little girls. He played with them, running races and picking blackberries, then dismissed two of them with three halfpence. They watched him carry 9-year-old Fanny Adams up the hollow, telling her, “Come with me, and I will give you twopence more.”

Searchers found Fanny’s head on a hop pole. Both eyes had been gouged out and one ear torn off. Her arms were found in two locations, one hand still holding two halfpennies. Her heart had been scooped out of the upper torso, one foot was found in a field of clover, and her legs were assumed to have been taken by River Wey. There was no evidence of sexual assault because her lower torso was never found.

Baker couldn’t explain the bloodstains on his cuffs and argued only that his knife was too small to have done the work. He was found guilty of wilful murder and hanged on Christmas Eve.

His diary entry for Aug. 24 read, “Killed a young girl. It was fine and hot.”

It’s legal for me to expose your infidelity.

And it’s legal for me to seek $10,000 from you in a business transaction.

So why is it illegal for me to blackmail you for $10,000?

“Most crimes do not need theories to explain why the behavior is criminal,” writes Northwestern law professor James Lindgren. “The wrongdoing is self-evident. But blackmail is unique among major crimes: no one has yet figured out why it ought to be illegal.”