10 Most Notorious Criminals In American History

Violence and crime stain the pages of U.S. history, and sadly, they're all but certain to be part of our future.

Still, the criminal mind fascinates us, and you couldn't name or number all the TV shows, movies and novels that all but glamorize true crime.

Selecting 10 of America's most notorious criminals is a daunting task. Of course, there is no single criterion, and morbid factors, such as body count, sadism and notoriety must all be considered. Keeping that in mind, we've assembled a list of some of America's most dangerous and violent villains.

1. Al Capone

Infamous American crime czar Al “Scarface” Capone was once king of the Chicago rackets. A Prohibition-era gangster, he ruled a multimillion-dollar empire in the 1920s that was fueled by illegal booze, gambling and prostitution. Capone is also suspected of being the mastermind behind the 1929 Saint Valentine’s Day Massacre in Lincoln Park that left seven of his enemies dead. Capone’s reign as ruler of Chicago’s gangland ended in 1931 when he pleaded guilty to tax evasion and prohibition charges. After serving seven years and six months in federal prison, which included a stay at Alcatraz, Capone was paroled on Nov. 16, 1939. By that time, however, he suffered from paresis derived from syphilis. Capone w

ent into seclusion at an estate near Miami, Fla., where he died of a stroke and pneumonia on Jan. 25, 1947.

2. Charles Manson

Charles Manson was leader of the Manson Family, a quasi-commune that he formed in California in the late 1960s. Manson believed in an impending apocalyptic race war, which he termed "Helter Skelter." He orchestrated a series of gruesome murders on consecutive nights in an effort to help precipitate the race war. In 1969, Manson and his followers were convicted in the slaying of actress Sharon Tate and several others. Initially sentenced to death, Manson's sentence was later commuted to life in prison. Manson was denied parole for the 12th time in April 2012.

3. Ted Kaczynski

Authorities accused Ted Kaczynski of being the domestic terrorist responsible for more than a dozen bomb attacks in multiple states between 1978 and 1995 that killed three people and injured 23 others. The attacker, who called for the "destruction of the worldwide industrial system," was dubbed the Unabomber because many of his early targets worked at universities and airlines. Investigators zeroed in on Kaczynski after his brother, David Kaczynski, informed the FBI that a manifesto attributed to the Unabomber appearing in The New York Times and The Washington Post was similar to papers his brother had written. Ted Kaczynski was ultimately sentenced to life in prison without the possibility of parole.

4. Tom Horn

Tom Horn was a man of many hats. He was an Army scout, a lawman, an assassin and an outlaw. His name may not be as well-known as that of Billy the Kid or Jesse James, but he was certainly one of the most cold-blooded killers of the Wild West. During the late 1880s, Horn worked for the Pinkerton Detective Agency as a bounty hunter. While he initially seemed like a good fit, his capacity for violence did not go unnoticed. In 1894, he was forced to resign after he was linked to 17 murders. Stripped of his badge, Horn became a killer-for-hire. His typical target was cattle rustlers and he is believed responsible for the deaths of at least 20 rustlers. In 1901, Horn was linked to the murder of 14-year-old Willie Nickell. The teen was the son of a rancher. Horn's guilt remains a subject of debate for historians. Regardless of his level of responsibility, Horn was executed by hanging in Cheyenne, Wyo., on November 20, 1903, the day before his 43rd birthday.

5. Adam Lanza

Adam Lanza, a 20-year-old recluse from Connecticut, brought terror to Newtown's Sandy Hook Elementary School on Dec. 14, 2012. The troubled young man, armed with a semi-automatic rifle and a handgun, entered the school and fired 154 shots in a span of about five minutes. In the aftermath, 20 first-graders and six educators were left dead. Lanza then took his own life. It was not until later that day that authorities discovered an additional casualty — Lanza's mother, Nancy. He had killed her in their Newtown home prior to the school shooting