The “worst” American crime is subjective and can be defined by the severity of the act or its impact. Some of the most notorious crimes include terrorist attacks like 9/11, which killed 3,000 Americans, and assassinations of public figures like President John F. Kennedy and Martin Luther King Jr. On a smaller scale, infamous serial killers such as Ted Bundy and Patrick Kearney committed numerous murders over a period of time, while the torture and murder of Sylvia Likens represents a horrific act of violence perpetrated by a caregiver and neighbors. 

Major terrorist attacks

• 9/11 attacks: In 2001, the most lethal terrorist attacks in history killed nearly 3,000 Americans. 

Assassinations

• Assassination of President John F. Kennedy:Killed in 1963, the assassination remains a significant event in American history.
• Assassination of Martin Luther King Jr.:Assassinated in 1968, his death was a major blow to the Civil Rights Movement. 

Serial killers

• Ted Bundy: Abducted, sexually assaulted, and murdered dozens of women between 1974 and 1978. He confessed to 30 murders but may have committed more.
• Patrick Kearney: Known as the “Freeway Killer,” he is suspected of killing 43 people between 1965 and 1977 in Southern California.
• Belle Gunness: A Norwegian-American serial killer who murdered her husbands and boyfriends for life insurance money. 

Other horrific crimes

• The murder of Sylvia Likens: In 1965, a teenage girl was tortured and murdered by her caregiver, her children, and several neighborhood children over a period of three months.
• TWA Flight 847 hijacking: A hijacking that resulted in the murder of a U.S. Navy diver.
• White-collar crimes: The collapse of the Enron Corporation led to the largest white-collar crime investigation in FBI history.