Mass killers target Americans once every two weeks on average, in attacks that range from robberies to horrific public shooting sprees such as the massacre Friday of 27 people in Newtown, Conn., a USA TODAY examination found.
Using news accounts and FBI records from 2006 through 2010, the most recent years for which complete records were available, USA TODAY identified 156 crimes that met the FBI definitions of mass killings, where four or more people were killed.
All told, the attacks killed 774 people, including at least 161 young children.
The review offers perhaps the most current, complete picture yet of a crime that is frighteningly common and not widely understood.
Everybody is surprised when they hear its dozens a year, said Northeastern University criminologist James Alan Fox, who has studied mass murders. People dont understand them. When they think of mass murders, they only think its random.
USA TODAYs examination did not include murders during the last two years, both of which were marked by a series of high-profile public shootings, including a rampage this year at an Aurora movie theater that left 12 dead and 57 injured, and an attack on a Sikh temple in Wisconsin that killed six.
Without more complete records, it is impossible to know whether mass killings increased during those years though they have become less common since the mid-1990s, said to Grant Duwe, director of research at the Minnesota Department of Corrections, who has studied mass murders.
The killings between 2006 and 2010, however, offer a portrait of mass murder that in many ways belies the stereotype of a lone gunman targeting strangers: Lone gunmen, such as the one who terrorized Sandy Hook Elementary School last week, account for fewer than half of the nations mass killers. About a quarter of mass murders involve two or more killers.
A third of mass killings didnt involve guns at all. In 15 incidents, the victims died in a fire. In 20 others, the killer used a knife or a blunt object.
When guns were involved, killers were far more likely to use handguns than any other type of weapon. Children frequently are victims. At least 161 who died in mass killings about 1 in 5 were 12 and younger. Mass murderers tend to be older than other killers, with an average age of nearly 32. Like all killers, they are overwhelmingly men.
Fridays massacre in Newtown has turned a whole new page in the nations long-running debate about guns, said Rep. Carolyn McCarthy, D-N.Y., a leading proponent of tighter gun laws.
Parents and grandparents, dads, gun owners are thinking that their children at any time at any place could have someone come in and do this kind of massacre, McCarthy said.
But for all the attention they receive, mass killings still accounted for only a tiny fraction about 1 percent of all the Americans who were murdered during those five years. More died from migraines and falling out of chairs than were murdered by mass killers, according to death records kept by the U.S. Centers for Disease Control and Prevention. Three times as many people died from sunstroke.
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