Violent crime spiked in the United States after the emergence of the Covid-19 pandemic. In 2020, the nationwide homicide rate jumped by 30%, to the highest level since 1995, according to the Centers for Disease Control and Prevention – led by an all-time high for gun murders.

More disturbing than the increase is the fact that fewer murders are being solved overall. According to FBI statistics, the murder clearance rate — the proportion of homicides for which police report an arrest — has been on the decline for decades.

About half of all murders in the country remain unsolved, compared to about 30-40% of them in the 1960s. In some states, like New Mexico, Ohio, and Michigan, the unsolved rate is as low as 60%. (See the states where the murder rate is rising.)

The explanation for this increase in unsolved murders since the 1960s is in part because older clearance rate statistics are less reliable. But over the past 40 years, guns have increasingly been used to commit these killings, and as crime analyst Jeff Asher pointed out in an interview in The Atlantic last year. “Firearm murders are much harder to solve. They take place from farther away. You often have fewer witnesses. There’s less physical evidence.” (These are the states where people are buying the most guns.)

Whatever the cause for this increase in unsolved homicides, most are forgotten by all but the surviving family and friends. Some, however, remain in public memory for decades.

24/7 Tempo has compiled a list of some of the most famous unsolved crimes – homicides and otherwise – in America. We drew information from the FBI, various media reports, and other sources, including regional publications. We focused on crimes that have gone unsolved for at least 15 years based on the most current information available. The list is by no means comprehensive and we used editorial discretion to determine which unsolved crimes most captivated the public’s interest and generated significant media coverage.

Click here to read more about 22 famous unsolved crimes in America

A vast majority of the most famous unsolved crimes in American history involve murder, from the killings of Andrew and Abby Borden in 1892, which was the subject of a Hollywood film as recently as 2018, to the as-of-yet unsolved assassinations of New York rappers Tupac Shakur and Notorious B.I.G. in 1996 and 1997.

Unsolved crimes other than murder include a brazen art heist worthy of a crime thriller, an infamous hijacking, and an intricate jail break at the former Alcatraz Federal Penitentiary that may or may not have been successful.