Former U.S. postal worker Joseph Harris shoots two former co-workers to death at the post office in Ridgewood, New Jersey. The night before, Harris had killed his former supervisor, Carol Ott, with a three-foot samurai sword, and shot her fiance, Cornelius Kasten, in their home. After a four-hour standoff with police at the post office, Harris was arrested. His violent outburst was one of several high-profile attacks by postal workers that resulted in the addition of the phrase “going postal” to the American lexicon.

Harris, who was born in prison and had a lifetime of psychiatric problems, was fired from his job in April 1990. Harboring a grudge against his ex-employer, he began to stockpile automatic weapons, grenades, and ninja swords. Two years later, he learned that he had lost as much as $10,000 by investing it with broker Roy Edwards. Dressed in a black ninja costume, Harris entered Edwards’ Montville, New Jersey,home and handcuffed the family. After sexually assaulting Edwards’ wife and two daughters, he shot Edwards to death. Since hundreds of investors had lost money while dealing with Edwards, police never even considered Harris a suspect in his death until after the mass slaying on October 10.

Arguing that he was insane, Harris’ lawyers said that he had told psychiatrists that he was driven by the “ninja spirit” to commit the crimes. In 1992, Harris was convicted of both the Montville and Ridgewood attacks and was sent to death row. But in September 1996,two daysbefore a New Jersey State Supreme Court battle to overturn its death-penalty law was to start, he died of natural causes.

From 1983 to 1993, there were 11 murderous rampages in U.S. post offices. On August 20, 1986, the worst of these incidents took place in Edmond, Oklahoma. Pat Sherrill, who was about to be fired, killed 14 mail workers, wounded another five, and then shot himself to death as the SWAT team arrived.