The number of serial killers active in the U.S. is a difficult if not impossible number to determine. Law enforcement agencies just don't gather that kind of information.
One way to approximate how many killers may be active is to look at violent crime trends.
While crime rates in major cities has gone down, the rate of stranger (the offender was unknown to the victim or no link between the victim and the offender could be determined)has continued to increase.
That could be an indication that serial crime is on the rise in the U.S.
Katherine Ramsland has the following to say about violent crime trends and stranger homicide in her book "The Science of Cold Case Files".
Homicide trends in stranger to stranger murders or where the relationship between the killer and victim is unknown do provide some evidence that suggests an increase in serial murder. In the past the vast majority of murders were committed by individuals who had formed some type of relationship or acquaintance with their victims. This is no longer the case. In 1965 only 5% of murders were committed in unknown circumstances. In 1992 this figure had increased to 28%. In 1992 murders by strangers and unknown persons represented 53% of all murders in the United States that were reported to the FBI. In 1999 the figure for murders by strangers or where the relationship was unknown was 51.3 % of the total, very close to the 1992 figure. Whereas in 1965 nearly 1 out of 3 murder victims was killed by a person or persons within his or her family in 1999 the figure had fallen to only 13.8 % supporting the trend away from murders within a family.
Law enforcement officials are quick to point out that murder rates hit an all time low in the United States in the 1990's. In an effort to put a positive light on the problem of violent crime in America, but, these statistics and any comforting thoughts of safer streets it brings, are very deceptive . While the murder rate did steadily rise in the 1960's - 1980's, law enforcement’s homicide clearance rates during this period averaged around 80% .
“In the 1960's just over 9,000 homicides were recorded in the US after that, the murder rate steadily rose with the greatest increase occurring during the 1980's. In 1985, the department of justice recorded 18,980 homicides. Serial killings also increased during this decade and by 1993 the homicide count stood at 24,530. Even worse the percentage of murders that were random in nature increased. In 1992, murders by strangers rose to 53 percent of recorded homicides and it was much harder in such cases to assess motives and develop leads. By 1995 there were an unprecedented number of unsolved crimes on the books. The clearance rate had dropped from 91 percent in 1965 to 65 percent in 1992." While there are less homicides reported now clearance rates have plummeted to slightly greater than 50%. “In 2001 only 62.4% of homicides were cleared...Today ones chance of getting away with the perfect murder are steadily creeping toward 50/50".
The cause for this new all time low clearance rate is the rise of stranger killing, meaning the offender is unknown to the victim and no motive or connection can be found. Law enforcement tells us that the first 24-48 hours in a homicide investigation are critical in determining a motive, a connection and finding witnesses . Stranger killing cases like these, where those factors cannot be established , become cold quickly.
What all this means, is that, while your chance of becoming the victim of a homicide is now lower than ever, law enforcement’s probability of solving the crime when they are called to investigate a murder is also lower than ever.
“By 1995 when the aggregate number of homicides in the United States peaked, an extraordinary 55% of victims were slain by strangers and persons unknown a total of 11,800 people....strangers means that the investigation determined definitively that the victim did not know the killer. This includes not only random victims of serial killers but also for example store clerks shot dead by strangers in the course of a robbery. Persons unknown on the other hand means precisely that investigators simply did not know whether the victim knew the murderer, it does not necessarily mean that the perpetrator was a stranger only that the relationship to the victim was not determined or not entered into the supplementary report upon which statistics are based.” 57% of all murders committed in the year 2001 were perpetrated by strangers or persons unknown.
While your chance of becoming the victim of a violent crime is now lower than ever, the chance of the police catching your attacker, if you are victimized is also now lower than ever.
It would appear that American society(while serial killing isn't only an American phenomenon) is "breeding" serial killers at an alarming rate. Part of that may be due to our modern society. Everything is about me, me, me.
Also, serial killers have the ability to objectify their victims. The victim isn't a person, he or she is an object to be used and abused by the killer. It's extermely easy in our modern life to see others as less than equals.
Years ago, if someone were to need to do banking, they would walk into the office and speak to the teller, make small talk while the transaction is being made and then leave. In 2005 if you need to do banking, you can bank 24/7 on the internet (no human interaction required), or drive up to the ATM (still no human interaction) need to pay your car insurance, call the 24 hours customer support number and find...an automated service. For many American's the only "human" interaction they get is chat rooms, sure they are "talking" to another living, breathing, thinking person. But it's easy to see the words and not think about the "person" on the other end of the computer as an actual..PERSON.
Steven Eggar in his book The Killers Among Us 2nd edition. Gives more statistics about crime.
Serial murder as indicated earlier is generally a stranger to stranger crime. Thus one must look to this category of homicide to attempt to determine if the number of serial murders since no evidence is found in the literature of monitoring or tabulating this phenomenon. In the past, homicide have typically been separated into 3 categories. About 1/3 have been between intimates family members or lovers 1/3 have been between acquaintances and 1/3 have been between strangers. In the 1960's the rate in the last category began to rise dramatically while the other 2 have remained relatively stable. Frank E Zimring director of the University of Chicago's Center for Studies in Criminal Justice says that this classification needs to be examined much more carefully. He states "that's as specific as police agencies get with that category (between strangers) and it's not enough. We need to know who these strangers are and why the rate is going up".
Morris and Bloom Cooper analyzing victim killer relationships in homicides in England between 1957 and 1962 find that is was abundantly clear that homicides out of the blue in which the victim is struck down without reacting in any way is exceptionally rare. This has certainly changed at least in the United States. Kiger found a dramatic increase in stranger to stranger killings and he argued that these types of slaying were becoming more and more prevalent, quadrupling in the 1970's. Gilbert's analysis of homicide victims in San Diego found that between 1970 and 1980 nearly 50% of all homicide victims did not know their killers. During this period, there was a 60% increase in all reported violent crimes and the criminal homicide rate increased from 7.8 to 10.2 per 100,000 population.
The centers for disease control analyzed all homicides reported to the FBI between 1976 and 1979. Results of this analysis reveled that during this period 13% of homicides were committed by strangers and in 29% of he offenses the offenders were unidentified. In analyzing the same data for circumstances of homicides 20% were found to be indeterminable. In most instances, serial murders would be found within these categories since they are frequently stranger to stranger killings or murders in which the circumstances may not yet be determined.
In 1999 15,533 criminal homicides were reported nationally to the FBI for a rate of 5.7 per 100,000 population. This represents an 8% decreased from the previous year a 28 % decline from 1995 and a 34% decline from 1990. When population increases are taken into account the murder rate still shows a dramatic increase during this time. The 1993 rate was 9% higher than the 1989 rate and 20% higher than in 1984. If we look at 5 and 10 year periods we still see a dramatic increase until the mid-1990's when murder rates begin to decline dramatically.
It's difficult if not impossible to say with any certainty how many serial killers may be operating in the U.S. at any given time. But isn't it time that we find our lost humanity before serial crime becomes an epidemic in this country?
The Killers Among Us 2nd edition by Steven A. Eggar Pearson Education LTD 2002
Ramsland Katherine The Science of Cold Case Files Penguin Group USA 2004