These 20 Cases Changed American Law Enforcement Forever

For centuries, the United States lacked a centralized agency capable of handling multi-state or national intrigue crimes. That all changed in 1908 with the formation of the Federal Bureau of Investigation, under the leadership of J. Edgar Hoover. In a matter of years, the FBI grew into a formidable agency known for solving complex and high-profile cases in the U.S.

Over the decades, the FBI has investigated some of the most notorious crimes in U.S. history, with its remarkable team of agents bringing justice in cases that captivated (and still continue to captivate) the nation and the world. However, despite their best efforts, not all of these FBI cases ended in resolution, with many remaining unsolved to this day.

24/7 Tempo uses case records from the FBI and other historical sources to bring you some of these startling unsolved cases and cases that ultimately shaped law enforcement in the U.S. Let's take a closer look at this events and how the FBI was involved now.

This post was updated on July 30th, 2025, to reflect additional information.

• Outcome: The Rosenbergs were executed in 1953

During the first years of the Cold War, the FBI arrested several members of a spy ring that included Julius Rosenberg and his wife Ethel who were accused of passing along atomic secrets to the Soviet Union. They were found guilty of espionage and became the first and only Americans executed for espionage in 1953 during the Cold War.

• Outcome: Unsolved

During a routine early morning bed check at Alcatraz prison on June 12, 1962, authorities discovered that three convicts were not in their cells: John Anglin, his brother Clarence, and Frank Morris. In their places were dummy heads made of plaster, flesh-tone paint, and actual human hair. The prison went into lockdown, and an intensive search began. It is not known if the escapees drowned or had made the only successful escape from The Rock.

• Outcome: Unsolved

On the morning of Jan. 15, 1947, a mother her child out for a walk in a Los Angeles neighborhood encountered a gruesome sight: a young woman's body was sliced in half at the waist. Despite the extensive cuts to her body, there was no blood, indicating that she was murdered elsewhere. The young woman was Elizabeth Short, a 22-year-old aspiring actress. She would be dubbed the "Black Dahlia" by the media for her alleged preference for sheer black clothes and for the "Blue Dahlia" movie out at that time. The crime remains unsolved.

• Outcome: 8 people found guilty for armed robbery

On the evening of Jan. 17, 1950, employees of the security firm Brinks, Inc., in Boston, were returning sacks of undelivered cash, checks, and other items to the company safe. Just before 7:30 p.m., five men entered the building, bound the employees, and grabbed the loot. They swiped more than $1.2 million in cash and another $1.5 million in checks and other securities, the largest robbery in the U.S. at the time. Eight men were eventually found guilty of the robbery.

• Outcome: Suspect confessed to kidnapping and murder and executed

Charles S. Ross, the wealthy president of a greeting-card company, was driving toward Chicago on Sept. 25, 1937, when he was pulled over and kidnapped at gunpoint by two men. Ross and one of the kidnappers, James Atwood, were killed by John Henry Seadlund, who was eventually caught and executed.

• Outcome: Unsolved

A man who identified himself as D.B. Cooper hijacked Northwest Orient Flight 305 out of Portland, Oregon, on Nov. 24, 1971. He demanded and received $200,000 in ransom money upon landing in Seattle. The plane took off for Mexico City, and during the flight he parachuted into the woods in the American West and was never seen again.

• Outcome: Man served 28 years of a 35-year jail term

Special Agent Edwin C. Shanahan sought to apprehend Martin James Durkin, a professional automobile thief, for violation of the National Motor Vehicle Theft Act. On Oct. 11, 1925, Shanahan became the first FBI agent slain in the line of duty while trying to arrest Durkin in Chicago. It was not a federal offense to kill a special agent until 1934. Durkin served 28 years of a 35-year term and was released in 1954. He died in 1981.

• Outcome: Kidnappers caught and convicted

Frank Sinatra, Jr., son of iconic singer Frank Sinatra, was kidnapped on Dec. 8, 1963, at a lodge in Lake Tahoe, Nevada, by two 23-year-old men from Los Angeles and held for $200,000 ransom. Young Sinatra, who was trying to start his own singing career, was found unharmed and the money was recovered. Three kidnappers were convicted.

• Outcome: Suspect sentenced to two consecutive life terms

FBI Agents Jack Coler and Ronald Williams were murdered on June 26, 1975, at Pine Ridge Indian Reservation by Leonard Peltier in the southwest corner of South Dakota. Peltier, who had an outstanding warrant for his arrest at the time of shootings, was sentenced to serve two consecutive life terms.

• Outcome: Jack Gilbert Graham found guilty of murder and executed

On Nov. 1, 1955, United Air Lines Flight 629 with 44 people aboard took off from Stapleton Airport in Denver bound for Portland, Oregon, but an explosion on the plane caused it to crash on a beet farm near Denver. The downed aircraft was the work of Jack Gilbert Graham, who stood to inherit insurance money upon the death of his mother who was on that plane.

• Outcome: Suspects sentenced to life imprisonment

Army deserters James Edward Testerman and Charles J. Lovett gunned down special agent Hubert J. Treacy, Jr. on March 13, 1942, in a restaurant in Abingdon, Va. They were apprehended after a gun battle and sentenced to life in prison.

• Outcome: Kidnappers executed

Bobby Greenlease Jr., 6-year-old son of a wealthy car dealer, was kidnapped from school in Kansas City, Missouri, on Sept. 28, 1953, held for $600,000 ransom and then murdered. Suspects Carl Hall and Bonnie Heady were arrested and a jury in the federal court in Kansas City, recommended the death penalty after only an hour and eight minutes of deliberations. They were executed in the gas chamber on Dec. 18, 1953.

• Outcome: Oswald gunned down by Jack Ruby

President John F. Kennedy was assassinated in Dallas on Nov. 22, 1963. The FBI conducted about 25,000 interviews and chased tens of thousands of investigative leads and came to the conclusion that assassin Lee Harvey Oswald acted alone in the killing of the president.

• Outcome: Three suspects sentenced

On May 24, 1935, George Weyerhaeuser, the 9-year old son of lumber tycoon J.P. Weyerhaeuser of Tacoma, Washington, disappeared on his way home from school and was held for ransom initially put at $200,000. FBI agents apprehended three kidnappers and retrieved more than $157,000 of the ransom money.

• Outcome: John Elgin Johnson killed in shootout with FBI agents

In a scene that seemed to come out of a movie, Special Agent J. Brady Murphy was mortally wounded in a gun battle with murder suspect and career criminal John Elgin Johnson in a Baltimore movie theater on Sept. 25, 1953.

• Outcome: Cultist Larry Layton sentenced to life in prison

An investigation into abuse at Jim Jones' Peoples Temple the jungle of Guyana on Nov. 14, 1978, led to the death of California Congressman Leo Ryan and then the poisoning of more than 900 cultists, including more than 200 children.

• Outcome: Suspects arrested and convicted

The theft of a valuable diamond ring and $700,000 on April 10, 1959, by three men at the Krupp family ranch in Nevada led the FBI on a cross-country chase that ended with the arrest of a man in a hotel room in Elizabeth, New Jersey. The ring's diamonds were reassembled and the precious band was later bought at auction by Richard Burton for his then-wife Elizabeth Taylor.

• Outcome: Suspect killed, two others arrested

On May 3, 1938, Special Agent William R. Ramsey died from wounds that he sustained while attempting to arrest one of the suspects, Joe Earlywine, in an Indiana bank burglary that had taken place the previous year. Ramsey was able to shoot and kill Earlywine before he died. Two other paroled convicts were arrested.

• Outcome: Walter Moody executed in 2018

At the end of 1989, the nation was shaken by a series of bombings in the South targeting federal buildings, law officials, and the Jacksonville office of the NAACP. Judge Robert Vance was killed in his suburban Alabama home on Dec. 16, and Robert Robertson was slain two days later in Atlanta. The trail led to Walter Leroy Moody, who had harbored a grudge against Judge Vance over a previous case. Moody was executed in 2018.

• Outcome: Bruno Richard Hauptmann executed

Charles Augustus Lindbergh, Jr., 20-month-old son of the famous aviator and author Anne Morrow Lindbergh, was kidnapped on March 1, 1932, from the nursery on the second floor of the Lindbergh home near Hopewell, New Jersey. The child died during the ordeal and the kidnapper, Bruno Richard Hauptmann, was executed in the electric chair.

• Outcome: Suspects sentenced to life in prison

After forging an alliance in an Ohio prison, Albert Nussbaum and Bobby Wilcoxson robbed eight banks, amassed an arsenal of weapons, killed a bank guard, and set off several bombs in the nation's capital in 1961. The two had a falling out and were apprehended in the countryside outside of Buffalo. They were sentenced to life in prison.

• Outcome: Cattleman WIlliam Hale and his henchmen sentenced to prison

A series of murders committed against members of the Osage Nation in Oklahoma, who owned rights to recently discovered oil and earned royalties from its sale, was solved when the FBI apprehended business mogul William Hale and his henchmen. The story is the subject of the Martin Scorsese-directed film "The Killers of the Flower Moon."

• Outcome: Hearst found guilty of bank robbery and other charges; President Carter commuted her sentence

Patty Hearst, the granddaughter of newspaper magnate William Randolph Hearst on Feb. 4, 1974, was abducted from her dorm room at the University of California, Berkeley, by armed anti-capitalist radicals of the Symbionese Liberation Army in California. The SLA demanded a ransom of $2 million to feed the poor. Patty Hearst was brainwashed by the SLA and participated in a bank holdup and helped make explosive devices. She was captured on Sept. 18, 1975, and charged with bank robbery and other crimes. Her seven-year sentence was commuted by President Carter after she served two years.

• Outcome: Kaczynski pled guilty and died in prison in 2023

Sixteen incendiary devices sent by mail were detonated between 1978 and 1995, one exploding in the bay of an American Airlines plane and another sent to the president of United Airlines. In all, the bombs killed three people. The case was cracked when the the Justice Department OK'd the newspaper publication of a 35,000-word manifesto by the so-called Unabomber. Social worker David Kaczynski alerted the FBI to similarities between what was published and the writing style of his brother Ted. The FBI tracked down Ted Kaczynski to a shack in Montana. Kaczynski pled guilty and died in prison in 2023.

• Outcome: Man sentenced to 45-year term in 1973

On April 7, 1972, a man brandishing a hand grenade and a pistol hijacked a United Airlines flight bound for Los Angeles from Newark, N.J., with a stopover in Denver, and parachuted from the plane over Utah with $500,000 in ransom money. Vietnam War veteran and helicopter pilot Richard Floyd McCoy, Jr., was eventually tracked down and sentenced to a 45-year jail term for air piracy. In 1974, McCoy escaped from the federal penitentiary in Lewisburg, Pa., with two other convicts and was eventually killed in a shootout with law enforcement.

• Outcome: Convicted in 1999, died in prison in 2011
• Weinberger kidnapping done
• Outcome: Suspect executed in 1958

One-month-old Peter Weinberger was kidnapped from his Westbury, N.Y., home on July 4, 1956, by Angelo LaMarca, a cash-strapped taxi dispatcher and truck driver. He left a ransom note for $2,000 but panicked when police and the press swarmed the dropoff site for the money. He left the baby unattended and he eventually died. The FBI matched LaMarca's handwriting with his writing in a previous probation file and arrested him. He was convicted of kidnapping and murder and executed in 1958.

• Outcome: Chesimard escaped from prison and lived underground before being located in Cuba in 1984

Joanne Chesimard, a member of the extremist group Black Liberation Army, fled the U.S. and is wanted for domestic terrorism; bank robbery; unlawful flight to avoid confinement after escaping prison in New Jersey in 1979; and the murder of a New Jersey State Trooper. Chesimard was named a Most Wanted Terrorist by the FBI and is the first woman ever to make the bureau's list of top terrorists. She is thought to be living in Cuba.

• Outcome: Anti-government militant executed; co-conspirators sentenced to prison terms

The Oklahoma City bombing occurred when a truck packed with explosives was detonated on April 19, 1995, outside the Alfred P. Murrah Federal Building in Oklahoma City. The blast killed 168 people and left hundreds more injured. Anti-government conspirators Timothy McVeigh, Terry Nichols, and Michael Fortier were found guilty of perpetrating the worst domestic terrorist attack in U.S. history. McVeigh was executed, Nichols was sentenced to life in prison, and Fortier was sentenced to 12 years in jail and released in 2007.

• Outcome: Byron De La Beckwith convicted

Civil rights leader Medgar Evers was gunned down in front of his Mississippi home on June 12, 1963. Two all-white juries rejected testimony from FBI agents and witnesses to convict Ku Klux Klan member Byron De La Beckwith. The persistence of Evers' widow Myrlie Evers-Williams forced the FBI to reopen the case. New witnesses were located and De La Beckwith was convicted in 1994. He died in jail in 2001.

• Outcome: All were captured

In July 1941, before America entered World War II, FBI agents apprehended German spy Frederick Joubert "Fritz" Duquesne and 32 other German agents following a two-year investigation. A year later, the agency thwarted two teams of German saboteurs who landed on Long Island and Ponte Vedra Beach in Florida.

• Outcome: Bonnie and Clyde, Dillinger killed

Holdups of banks and other businesses were common in Depression-era America in the 1930s, and the crimes of robbers Bonnie Parker and Clyde Barrow and John Dillinger commanded the nation's attention. In 1934, Bonnie and Clyde were slain in a hail of bullets from law enforcement, and later that year, and Dillinger was killed by special agents outside the Biograph Theater in Chicago while resisting arrest.