He was a recluse who spread terror through the mail for 18 years. Two men died and more than a dozen were injured , but Ted Kaczynski wasn't known as the Unabomber until his brother tipped off the FBI. Kaczynski's Manifesto, published in major newspapers, set off a flurry of activity for the FBI: writing analysis and comparisons, DNA gleaned from a single postage stamp and finally, Kaczynski's arrest at his tiny cabin. The agents collected enough evidence, including the Manifesto itself, to convict Kaczynski. He is serving four life sentences plus 30 years with no chance of parole.

A stranger snatched an eight-year-old girl as she played in her Tucson, Arizona neighborhood. Within hours, a drifter who was out on parole for abducting and molesting children, but he was nowhere to be found and time had run out.

Street gangs in Washington D.C. enforced their territories with lethal violence. Authorities vowed to bring the entire gang to justice while the gang leader had fled to Africa.

Police and FBI agents track a serial killer in a cross-country manhunt.

A young woman was snatched from her home on a bright spring morning. After several days of searching, a former FBI profiler narrowed the suspect list to one.

In a Georgetown coffee shop, three employees were shot to death. Metro D.C. police turned to the FBI for help, hoping the Bureau’s technical expertise could bring justice for the victims of the triple homicide.

In a suburb of Las Vegas, two robbers ambushed an armored car, killing both guards and seizing thousands of dollars. Authorities linked the crime to a series of armed robberies on gambling houses, including the MGM Grand Hotel and Casino.

In 1994, a rash of home invasions plagued the Detroit area. Each time, masked men disguised as police officers broke in with assault rifles and stole money and jewelry. But when one homeowner shot back, the identity of the intruders was revealed.

A woman vanishes, and police suspect that her powerful ex-lover, a married man, was responsible. When investigators can't find the woman's body or the murder weapon, the FBI's only hope was to go undercover and turn brother against brother.

Masked bandits pulled off a daring mid-day bank robbery. With no evidence leaving behind, the FBI forced their own luck.

Glendale, Arizona mall, local authorities and the FBI scrambled to recover its cargo of nearly a million dollars.

A California man was found dismembered. The murder suspect was found six months later when he was caught robbing an Arizona bank and sentenced to life. When he escaped from prison, the FBI led a manhunt for the killer.

In the season 3 finale, Drug gangs terrorized Harlem, New York neighborhoods. After a 10-year-old boy became a victim, the FBI formed a task force called C-11, designed to dismantle the gangs.

A mother discovered her 10 year-old son was missing from his school. The search would cover a thousand miles. Agents were raced to find the kidnapper and the missing child.

The hunt for serial killer Angel Resendiz, also known as the "Railroad Killer."

No description available

A 14-year-old girl ran away from her mother's home and disappeared without a trace. A farmer later discovered the young girl's remains in an Illinois barn.

A young mother was gunned down in front of her children. Family members offered a startling clue of the secrets of the woman. Investigations revealed a web of money, drugs and murder.

An Indiana town was turned inside out when an officer was gunned down at point-blank range. A psychotic killer led investigators across the Midwest.

In the 1990s, a gang based in the U.S. Virgin Islands smuggled large amounts of cocaine into mainland America. In an investigation spanning from Georgia to South America, the FBI and DEA were able to identify the leader and bring down the drug ring.

Marine Captain Shirley Russell disappeared. FBI agents found her husband, himself a former Marine, was acting strangely. The FBI's intense investigation revealed a violent past.

FBI agents began investigating New York gas station mogul Gurmeet Dhinsa for gas pump rigging. They learned that he enforced his mob-like operation with brutal violence.

The 1997 Los Angeles Dunbar Armored robbery, the largest cash heist in United States history. Six masked robbers stole $18.9 million.

On June 19, 1985, convicted bank robber Terry Conner and his partner-in-crime, Joseph Dougherty, escaped on their way to Dougherty's trial. In September, the fugitives used Conner's old m.o. to make the biggest bank robbery in Wisconsin history.

In 1993, a robber surprised unsuspecting customers by dropping through the roof of a California bank. A local resident led police and FBI agents to the perpetrator. However, they learned that he had also masterminded a kidnapping – and had a hostage.