While stalkers come from different backgrounds and have different personalities, researchers have developed several widely accepted typologies of them. It is important to emphasize that, while stalker typologies can be helpful, they are only general classifications. Whenever possible, a properly trained professional should conduct a threat assessment. Individual stalkers may not precisely fit any single category, and often exhibit characteristics associated with more than one category. However, the typology can alert investigators and victim advocates to certain general characteristics exhibited by similar stalkers, and help them with threat assessment and safety planning.

One widely accepted typology of stalkers21 is based on the stalker's underlying motives, and includes the following categories:

Simple obsessional. This is the most common type. The stalker is usually a male, and the victim an ex-spouse, ex-lover, or former boss. The stalking sometimes results from the stalker's feeling the victim has mistreated him or her. In intimate relationships, the stalking frequently begins before a breakup.

Love obsessional. The stalker is a stranger or casual acquaintance to the victim, but is obsessed and begins a campaign of harassment to make the victim aware of his or her existence. This type often stalks a celebrity or public figure, but can also stalk a noncelebrity.

Erotomania. The stalker falsely believes that the victim is in love with him or her, and that, but for some external obstacle or interference, they would be together. The victim may be rich or famous, or in a position of power (e.g., a movie star, employer, or political figure). In this situation, the stalker could also pose a great risk to those close to the victim (e.g., a spouse or lover perceived to be "in the way").

False victimization syndrome. This is extremely rare and involves someone who consciously or subconsciously wants to play the role of victim. He or she may make up a complex tale, claiming to be a stalking victim. In such cases, the would-be victim is sometimes the actual stalker, and the alleged offender is the real victim.

Another typology used to classify stalkers identifies them by their relationship to the victim.22 This typology divides stalkers into two basic categories: intimate and nonintimate.† The following is a brief description of these categories:

† The typology terms actually used are "domestic" and "nondomestic." "Intimate" and "nonintimate" are used here for clarity.

Intimate. A former relationship exists between the stalker and the victim. There is likely a history of abuse, such as domestic violence, by the stalker. The stalker often seeks to reestablish a relationship the victim has tried to end.

Nonintimate. The stalker has no interpersonal relationship with the victim. He or she may choose the victim after a brief encounter, or simply after observing the victim. The victim is often unable to identify the stalker when he or she first becomes aware of being stalked. This type is subdivided into two categories:

• Organized. The relationship between the stalker and the victim is characterized by one-way, anonymous communication from stalker to victim. The stalker is methodical and calculating, and the victim usually does not know the stalker's identity.
• Delusional. The relationship between the stalker and the victim is based solely on the stalker's psychological fixation on the victim. The stalker is delusional and falsely believes he or she has a relationship or other connection with the victim.

Again, stalkers often exhibit behaviors from more than one typology. The typologies are an overview, and you should never use them as a substitute for a thorough threat assessment.

Stalkers are, by their very nature, obsessive and dangerous.23 Regardless of typology, you should always consider stalkers capable of killing their victims. Anyone the stalker perceives as impeding his or her contact with the victim, including police, prosecutors, and advocates, is also at risk. Some stalkers seek union with their victims through murder-suicide.24 Any suicidal statements or gestures the stalker makes should serve as an indication that the stalker is a high-risk threat. You should also examine the stalker's background for depression, psychiatric hospitalizations, and other indications that he or she may be suicidal.

Stalking's Impact on Victims

Unlike the case with many crimes, the legal definition of stalking covers not only the offender's behavior but also the effects on the victim. The victim's psychological responses and the changes the victim makes in his or her life as a result of stalking can all be used as evidence of the fear the offender has caused.

Stalking's impact is often wide-ranging, severe, and psychologically traumatic. Many victims feel constantly on alert, vulnerable, out of control, stressed, and anxious. Dealing with stalking can consume all their energy. They may experience a loss of trust, long-term emotional distress, and significant disruption of everyday living.25 Many seek psychological counseling.26 Victims' symptoms tend to worsen with each new incident, and may be compounded by concerns about the effects on their children and other secondary victims.27

Stalking can also trigger a wide variety of behavioral reactions. Many victims take steps to avoid being followed and spied on. They alter their normal routines, avoid going out alone, and give up leisure activities. To protect themselves, they may screen all telephone calls (at home and work) and change their telephone number, email and postal addresses, driver's license, and social security number.28, † More drastic action may include temporary or permanent relocation. They may move to another state or try to change their identity, often uprooting children in the process, leaving behind close friends and relatives, and abandoning careers.

† While victims can change their social security number, some victims have had problems as a result (for example, establishing credit or prior employment history, or getting a passport). Therefore, this option should be weighed carefully.

When the criminal justice system fails to protect victims from stalking, it makes it that much harder for them to recover from its effects.29

The Challenges of Policing Stalking

Stalking can be difficult to recognize, investigate, assess, and prevent for many reasons, including the following:

• Stalking is not a single, obvious, easily identifiable crime like assault, robbery, burglary, and most other offenses.
• Stalking, like domestic violence, often is not taken sufficiently seriously because it can involve acts the police may perceive as part of everyday courtship and intimate relationships. The police may mistake repeated telephone calls, letters, cards, and gifts from "would be" lovers for innocent romantic attention. However, when such gestures are part of a course of conduct that instills fear in the victim, they are being used to terrorize.
• Stalking behaviors are complex, varied, and unpredictable. Stalking takes many forms, and individual incidents may be very different. It is hard to be certain if and when stalking will escalate to violence.
• There is no single stalker profile to assist investigators.
• When blatant acts of violence occur, a pattern of stalking behavior may not seem significant.
• Effective investigations depend on gathering information from many sources.
• The stalker may commit crimes in different locations and be under investigation in multiple jurisdictions. The victim may live in one jurisdiction, work or attend school in another, and seek refuge in yet another. If the stalker threatens people connected with the victim, such as coworkers, family members, or friends, or vandalizes their property, different victims' names will appear on complaint reports.
• Stalkers are not easily deterred and tend to be obsessive. Therefore, conventional sanctions, including court orders forbidding contact with victims, may not necessarily make an impact. Many stalkers continue to harass their victims even after conviction; the stalking may escalate if they perceive court sanctions as minor. Others may see their trials as a way to stay in their victims' lives. Because the first prosecution and conviction may not end the stalking, more enforcement is often necessary.† Thus, it is important to keep in touch with victims and ensure that offenders are supervised. (Mental health agencies may have a duty to warn victims of imminent threats, and batterer's intervention programs often do not require confidentiality between offenders and staff; both can help monitor offenders.) 

† Investigators throughout the country have indicated that stalking cases can last years beyond the first conviction. It is not unusual for an offender to start stalking again before an anniversary, following a stressful event, or after any number of other triggers that renew the stalker's interest in the victim. 

Because stalking is an ongoing crime involving multiple incidents, police may have numerous opportunities to observe the stalker's behavior and make an arrest. Even in cases where the stalker does not contact the victim in person, police can generally piece together enough evidence to identify and locate the offender and make an arrest. The sooner police can document separate stalking incidents, the greater the chance of bringing the offender to justice before a case escalates to lethal levels.