Such a breach of trust is often at the heart of mail crime, and perhaps no case amplified this more than that of Jim Bakker, the televangelist host of The PTL Club. Dangling the carrot of a lifetime of annual vacations at his resort, Bakker used the mail and his television show to amass millions of dollars that he used to fund a luxury lifestyle. “The message is that you can’t lie to people and you can’t use the telephone and the mail to lie to people to get them to send you money,” remarked Deborah Smith, who prosecuted at his trial in 1989. In the case of Allen Stanford 20 years later, Clayton Gerber, a postal inspector, would also emphasize the mail’s intrinsic honesty, saying that Stanford’s victims were inclined to believe him because “people trust what they get in the mail.” Stanford was accused by the U.S. Securities and Exchange Commission of running a “massive Ponzi scheme,” later receiving a 110-year sentence for defrauding his investors of $7 billion and embezzling at least $1.6 billion for himself.

Stanford’s victims came from across the globe, demonstrating how the international reach of mail delivered by ship and then air aided such crimes. Some uses of international post were dubious more than criminal, such as when the Australian athlete Reg Spiers mailed himself home in 1964 to avoid paying for a plane ticket. (When another man attempted to copy Spiers’s feat a year later, he almost died in the process.) One ingenious criminal known as the jack-in-the-box thief used a similar technique, hiding himself on commercial flights and emerging midair to steal the mail. William DeLucia was eventually found out in 1980 when a trunk he was hiding in opened as it was unloaded.

But the internationalization of mail would also be used for darker, more devious crimes. In 1972 the Palestinian terrorist group Black September killed the Israeli diplomat Ami Sachori with a letter bomb sent to Israel’s embassy in London. The group, notable for using this method to attack its enemies, was actually following a path that goes back almost as far as the postal service itself. While Emily Davison is known for throwing herself in front of the king’s horse at Epsom Derby in 1913, two years earlier she had been sent to prison for “unlawfully and maliciously placing in a Post Office letter box a dangerous substance likely to injure” bystanders. Suffragettes often used ink to damage mail in post boxes, but they also resorted to crude letter bombs, sometimes containing liquid phosphorus in fragile glass tubes.

In the following decades, the letter bomb would become a common tool of political agitation. One example comes from the Scottish National Liberation Army, a small organization modeled after militants in Northern Ireland. The so-called Tartan Terrorists often turned to the letter bomb in their campaign against the British state, which reached its peak in the 1980s and 1990s, sending devices to figures including Margaret Thatcher and the Princess of Wales. The letter bomb also attracted fringe groups such as the Japanese doomsday cult Aum Shinrikyo. After using sarin nerve agent to kill 13 people on a subway train in 1995, the group sent a parcel bomb to the office of Tokyo’s governor in an effort to disrupt the police investigation, instead blowing off the fingers of a secretary.