Becoming Evil: Rampage

While mass killings have been seen throughout American history, serial killing were recognized as a separate issue in the 1970's.

When Charles Whitman opened fire on a Texas university campus in the 1960s, it became the quintessential example of public, random killings.

While some killers commit calculated and planned murders, it's far more likely for a mass murderer to go on an impulsive, rage filled killing spree.

Many mass killings have been committed against people of specific races in acts defined as hate crimes.

It's usually a place of security, but workplaces can become the target of a disgruntled worker with a gun.

While Columbine is one of the most well known examples of a school massacre, the phenomenon is not a new one.

James Ruppert killed 11 of his family members on Easter Sunday.

Cult leaders attract devoted and fanatic followers, and sometimes convince them to take their lives in order to reach eternal peace.

To evade detection or consequences, some killers resort to fires or explosions to carry out their attacks on the public.

In a twisted attempt to send a political message, some resort to mass murder.