The Investigation of Serial Killers: Profile to Apprehension

Serial killings occur when the murder is involved with three or more murders with a significant “cooling off period” in between events. Serial murders tend to be high-profile cases and the names of these murderers are forever imprinted on the society involved. Such names include: Jack the Ripper, Ted Bundy, Aileen Wuornos and David Berkowitz.

The process of apprehending these murderers has evolved over time. Through the use of criminal profiling and an extensive investigations process, The FBI and local law enforcement agencies have been able to capture many infamous serial killers.

Criminal Profiling

The investigation of serial killers often begins with a profiling process. Different law enforcement jurisdictions have their own profiling process, but each has been adapted from the original FBI model. According to the Department of Justice, “Criminal profiling uses the behavioral characteristics of the offender as its basis”.  The FBI’s profiling program began in 1970 as an informal analysis, and evolved into one profiling manager, seven active profilers and several crime analysts.

In a single year, they may receive up to 600 requests for profiling. Murder investigations, including that of serial killers, are handled in the following way:  mental health professionals try to understand the perpetrator by using psychiatric concepts. Second is the use of a criminal profiler, who determines behavior patterns through investigative work. The process of creating a criminal profile is as follows:

  • Data is collected and studied. This will include all crimes of which the killer is suspected; evidence and relevant interviews;
  • Each crime scene, or “situation” is reconstructed;
  • Hypotheses of the crime, motive and possible future victims are generated;
  • The above are used to create a profile;
  • The profile is tested;
  • Results are reported back to the investigation team.

The objective of profiling is to determine what the perpetrator is thinking in order to predict what they might do next. There are six stages to the profiling process.

Profiling Inputs Stage

This stage begins with a summary of each murder. Investigators take note of any evidence that is indigenous or specific to the area in which the murder was committed.

The investigators will need background information on each victim, including domestic situation (single, married, living alone or with roommates), employment, habits (was the victim predictable from day to day), and criminal history. The investigators will also gather and study forensic evidence, including autopsy and toxicology reports. The most crucial part of this process is that suspect information must not be included. This sort of speculation would serve to bias the investigators and cause them to create a profile that matches the suspect.

Decision Process Models Stage

This process begins by using the available data to form potential patterns.  These patterns are determined by the following:

1. Homicide Type and Style

   Homicides are categorized according to their type and style. Some forms of classification are:

  • Single homicide: One victim/one crime scene
  • Double homicide: Two victims/one crime scene
  • Triple homicide: Three victims/one crime scene
  • Mass murder: More than three victims at a crime scene
  • Classic mass murder: victims are unrelated
  • Family mass murder: members of one family are murdered, killer is related somehow.

2. Primary Intent of the Murderer

Murder is not always the primary motivation, even in serial killings. The killer’s primary intent might have been criminal (theft, destruction of property, etc.), emotional, or sexual. In the 1984-1985 case of Leonard Lake and Charles Ng, their primary intent was sexual and the killings were an unfortunate after thought.

3. Victim Risk

Victim risk factors might include age, occupation, lifestyle and location. The information garnered from the risk of each victim helps to contribute to the profile of the killer.

4. Offender Risk

This risk determines how likely it is for the offender to be caught during the crime.  High-risk activity for an offender would be killing victims in highly populated areas, such as a busy street. Low-risk would include a home invasion.

5. Escalation

At this stage, profilers use evidence compiled about each individual crime in order to determine the sequence of events. This helps to determine if the killer will have a need to not only keep going, but commit more heinous acts. This was true in the case of David Berkowitz, the Son of Sam killer, who began by stabbing a young girl and escalated to shootings.

6. Time Factors

Profilers must consider the length of time required to commit each crime and the length of time (in hours, days, weeks, etc) in between each murder. The latter is significant because the killer will need time to determine his next victim and his strategy for getting close to and killing that victim.

Crime Assessment Stage

This is the point at which the profilers will put together all the data and create a sequence of events for both the killer and the victim. The murder is determined to be organized or disorganized.  According to former police detective and novelist Ann Rule,  in her book The Stranger Beside Me, murderer Ted Bundy committed both types of murders.

Some were well planned out, often through the use of stalking his victims for hours or days beforehand, then approaching them. He often approached his victims by appearing as a victim himself (he would use a fake cast or pretend his car had broken down). The most bizarre aspect of this case is that Ann Rule had a friendly relationship with Ted Bundy before and during his serial killing career and had no idea of his true nature.

Criminal Profile Stage

The fourth stage of profiling requires the profilers to focus on the person committing the murders. It is important that the facts that have been acquired to this point meet the original reconstruction of the crimes.

Investigation Stage

Once the profile has been compiled, a report is then provided to the investigative agency (for example, another division of the FBI, or local law enforcement who requested the profiling assistance). When a suspect admits guilt, investigators must go back through the profile and verify the information.

The best way to describe the investigation process is to use an example, such as the investigation of Ted Bundy, who committed his murders from 1974 to 1978. Robert Keppel, Phd., described his interviews with Bundy in the compilation book, The Riverman. At this time, he was a junior detective with the King’s County Sheriff’s Department. None of the detectives had experience with a case of that magnitude. During the investigation, the team was able to compile a random list of details important to the apprehension of serial killers.

            The Tip Sheet

Keppel revealed that a great deal of useful information came from requests for tips from citizens. Keppel’s initial job was to prioritize the tips and follow up on them.


In the mid-1970’s, even police departments didn’t have access to PC’s. Computers of this time involved punch cards and a specific punch card operator to use the machine. Keppel had the idea of using the machine to compile different lists and determine how many times the same names appeared on different lists. This was how Bundy came to be a suspect.


The investigators did refer to a profile that had been developed, and it turned out that Bundy fit every aspect of the profile. Even without the technology we have today, profiling is a near-exact science. The profile on Ted Bundy was one of the earliest examples ever used.

            Calling Card

A killer is thought to leave behind “calling cards” when he (or she, as the case may be) performs certain acts or leaves behind certain evidence that links one murder to another. Keppel and his team eventually determined that Bundy’s calling card was bite marks.


When a serial killer has been able to commit his crimes for an extended period of time without being caught, he may eventually become careless, using less caution in the act of committing the murders. Such was the case with Bundy. Keppel believes that Bundy went to Florida and specifically the Chi Omega House in order to continue his crimes in warm weather and in a place where women wore bikinis. He didn’t stop there, however. Shortly after finishing his spree at the Chi Omega House, he broke into the apartment of a young woman named Cheryl, who had this to say:

She was still somewhat conscious and half nude, but lucky to be alive. Police discovered a mask at the foot of her bed. The mask that was found "resembled almost exactly the mask taken from Ted Bundy's car when he'd been arrested in Utah in August of 1975."      (Rule, 1980)

Ted Bundy was captured for the second and final time during a routine traffic stop – Bundy had stolen a VW with expired plates. He was 42 years old when he was executed in the electric chair by the state of Florida. He died at 7:16 a.m. on January 24, 1989. His last words were, "I'd like you to give my love to my family and friends."

The Man, the Myth…the Women?

It is a common myth that only men can be serial killers. This idea is just that, a myth. In The Riverman (1985), Keppler disputes the myth of the exclusively male serial killer when he discusses the case of Aileen Wuornos, a sometime prostitute who often killed her customers. In his book, Serial Murderers and Their Victims, Eric Hickey, Phd., discusses the phenomenon of female serial killers.

These are the quiet killers, every bit as lethal as male serial murderers, but we are seldom aware of one in our midst because of their low visibility.   (Hickey, 2001)

According to Hickey, female serial killers account for only 8% of all American serial killers. Their top most common methods for killing are:

  1. Poison (80%)
  2. Shooting (20%)
  3. Bludgeoning (16%)
  4. Suffocation (16%)
  5. Stabbing (11%)

Through his research, he compiled the following motives for female serial killers:

1. Money (74%) 2. Control (13%) 3. Enjoyment (11%) 4. Sex (10%) 5. Drugs, Cult involvement, cover up, or feelings of inadequacy (24%)

When females act alone, they often commit murders as a black widow (killing husband or partner), an angel of death (systematically killing people who are under her care), sexual predator (clear acts of sexual homicide), or for profit. There are many unsolved crimes that are thought to be the work of a woman acting with others.

Investigation: Then and Now

The case of Ted Bundy sent the investigation of serial killers and the profiling process in a different direction. Killers before Bundy were thought of like Jack the Ripper: ugly, inhuman, completely different from the norm. Bundy, however, was none of those things. Ann Rule described her experiences with him in this way:

I cannot superimpose the monster image over the man I remember. Think about using a  microscope where you gradually bring the two slides together.  I can't do that with him.  I remember him as I thought he was, and then as the monster, but not the two images together (Ramsland, 2004)

In his book, Serial Killers: The Method and Madness of Monsters, Peter Vronsky states that Ted Bundy was like “…the average, attractive college student with typical ambitions and a Volkswagen bug.” It was no wonder that Bundy’s killing spree spanned four years (1974 to 1978).

Modern investigation of serial killers involves a more extensive use of technology and newer methods. In her article “Mapping Murder…”, Jennifer Wilson describes the use of a computer program called Dragnet that takes compiled information and creates a map of where the offender might live.

 It takes the pinpoints of evidence on a map and turns the information into a `temperature' map as to where an offender might live. The redder it gets, the hotter the spot. Like predators in the wild, criminals are predictable. There is logic to where they commit their crimes. (Wilson,

Dragnet was recently used in a Las Vegas case where a predator was brutally attacking women. The police were unable to pinpoint the perpetrator, in spite of witnesses and what is usually considered to be the pinnacle of all evidence, DNA.  Dan Helms, a crime analyst with the Las Vegas Police Department, used Dragnet and found extraordinary results.  Using the program, a clear pattern emerged of the assailant’s attacks.  He was able to combine this pattern with the assailant’s profile and his typical methods of attack.  

The assailant was not only a rapist, but also a thief. Helms used the lines created by the assailant’s pattern of movements within the neighborhood to track his possible location. At that point, the program displayed a block of apartments where the police immediately found the perpetrator: a young man who lived with his mother and had no local criminal record. He was later identified by an astonishing eight of his victims and is now on trial.

Pop Culture of Serial Killers…Torturing The Victims?

The tragedy of serial killers should be a matter for introspection and sympathy. Unfortunately, our culture has forgotten about the victims and their families. These are the people who wait for their relatives to come home, not realizing that they’ve been murdered – only to watch on television as the serial killer claims more and more victims. As investigations become more and more public, the victim’s families pay the price.

Hundreds of books have been published on the subject of serial killers, and many movies have been produced.  There are several biographers for every serial killer. Missing from the bookshelves and the silver screen are stories from the victim’s (meaning, victim’s families) perspectives.  Slasher films often take a cruel approach as the murderer is made into a hero (as in “American Psycho” with Christian Bale).  Rather, they depict the serial killer as a suave, misunderstood individual who kills for fun while quipping one-liners.

In conclusion, the science of investigating serial killers has evolved tenfold since the time of Jack the Ripper. FBI profiling, high-tech investigative techniques and dedicated law enforcement professionals have brought the science to a new level. The modern serial killer has a great deal of reading to do.


  • Douglas, J.E. (Ed.). (1986). Criminal Profiling: A Viable Investigative Tool Against Violent Crime. Federal Bureau of Investigation.
  • Keppel, R, Birnes, W.J., & Rule, A (1985). The Riverman. New York, NY: Simon & Schuster.
  • Keppel, Phd., R.D. (2004). Serial Murder: Future Implications for Police Investigations. New York, NY: Berkeley.
  • Ramsland, K (2004). The Human Predator. New York, NY: Berkeley.
  • Rule, A (1980). The stranger beside me. New York, NY: Signet.
  • Vronsky, P (2004). Serial Killers: The Method and Madness of Monsters. New York, NY: Penguin Berkeley.
  • Wilson, J. (2002, November). Mapping Murder: Police Have a New Way of Catching Serial Killers, Rapists and Arsonists. Using Detailed Maps and Models of Behaviour, They Are Learning How Offenders Operate and Have Been Successfully Tracking Down Criminals. Geographical, 74, 14+. Retrieved October 22, 2006, from Questia database: