America's serial killers prey on women -- to an extent only hinted at by Hollywood films and best-selling novels.
According to never-before-released FBI data, women accounted for 70 percent of the 1,398 known victims of serial killers since 1985. By comparison, women represented only 22 percent of total homicide victims.
The FBI's Violent Criminal Apprehension Program (ViCAP), based in Quantico, Va., released the data at the request of Scripps Howard News Service. SHNS is conducting an investigation into the nation's more than 185,000 unsolved homicides committed since 1980.
According to the FBI's Supplementary Homicide Report, local police reported that about 33,000 homicides of women remain unsolved.
FBI agent Mark Hilts, head of the bureau's Behavioral Analysis Unit No. 2 that profiles serial killers, said "a large number" of serial killers act with a sexual motive.
"Sex can be a motivation, but it's a motivation in conjunction with something else -- with anger, with power, with control," Hilts said. "Most serial killers do derive satisfaction from the act of killing, and that's what differentiates them" from those who kill to help commit or conceal another crime.
Crime experts for decades have tried to define serial murder and to determine its causes and motivations. The Justice Department currently defines a serial killer simply as someone who kills two or more people in separate incidents, a definition that ignores the issue of motive.
The Justice Department for years has estimated that less than 1 percent of all homicides are committed by serial killers, but that assumption has come under question recently.
Retired FBI agent Mark Safarik, a veteran serial killer hunter, discounts the official definition of serial murder.
"Serial murder is more related to motive. We use a definition of two or more, but that's really just for research purposes," said Safarik, now of Forensic Behavioral Services International, a legal consultant firm based in Fredericksburg, Va. "For us, there is almost always some sort of sexual component to the homicide."
The FBI has been compiling victim data for 25 years. They also released information showing that nearly half of the victims of known serial homicides were in their 20s and 30s, although people of every age and from every region of the county have been victims.
"We look at homicides and attempted homicides. We look at sexual assaults. We look at unidentified human remains cases where homicide is suspected," said Special Agent Michael Harrigan, who headed ViCAP from 2007 to 2010 and agreed to release the data.
"We catalog this in a database ... to try to identify serial killers or serial offenders that transcend jurisdictional boundaries."
Among states, New York leads in a grim statistic: It has had 137 victims of serial murder since 1985. California has had 128 and Florida 112.
When shown the FBI data, criminologists and veteran homicide investigators asked why New York leads the nation. Does it lead because it has more serial killings or because it does a better job in detecting such killings?
"That surprises me. I thought the numbers would always be higher in California and some of the Southern states," said retired veteran New York City homicide detective Augustine "Gus" Papay.
California, which its immense population, ought to lead in every major crime statistic, Papay said. And he felt Southern states would be over-represented because of recently documented highway serial killings by Southern truckers.
Papay was a key participant in the successful hunt for Alejandro "Alex" Henriquez, convicted in 1992 of murdering a woman and two girls, including 10-year-old Jessica Guzman.
Papay said serial killers may be drawn to a major metropolitan area like New York City.
"They think it's easier to get lost in the big city. And think of all the victims! There are also sorts of different people here they could target," Papay said. "And maybe they think it will be harder to get caught here."
Calculated by population, the state of Washington leads the nation with 1.6 serial homicides per 100,000 people. But that is almost entirely due to Gary Leon Ridgway, Seattle's so-called "Green River Killer." He was convicted in 2003 of strangling 48 women and teenage girls, often prostitutes or hitchhikers he picked up. Washington showed 95 serial killings overall.