Determining the Predominant Aggressor

Last updated Dec. 26, 2018

Perhaps one of the most important steps law enforcement can take to properly address domestic and intimate partner violence is to undergo training to properly determine which party is the predominant aggressor. The International Association of Chiefs of Police (IACP) defines “predominant aggressor” as “the individual who poses the most serious, ongoing threat, which may not necessarily be the initial aggressor in a specific incident.”[1] The IACP also informs law enforcement officers that they are “expected to arrest any person who commits a criminal act(s) of intimate partner violence—unless there is a clear and compelling reason not to arrest (self-defense determination, lack of probable cause)—after a comprehensive investigation to identify the predominant aggressor.”[2]

Mandatory arrest laws, while originally-well intentioned, resulted in a greater number of arrested women in domestic violence cases.[3] Victims may utilize violence to pre-emptively avert an attack from the aggressor or in self-defense. However, law enforcement may improperly assess or document these situations, or even allow incidents to go unacknowledged.[4] Batterers may try to convince the police that the violence was mutual or that they are the victim. One study found that in the 3,078 incidents surveyed, there were 2,090 total arrests and 416 dual arrests.[5] The same study found that in states with primary aggressor laws, 8.6 percent of incidents ended with a dual arrest, compared to 19 percent in states without primary aggressor laws.[6]

If the predominant aggressor is misidentified, there could be harmful legal consequences for the victim, including the denial of custody of children, of housing rights, and of immigration rights. Additionally, without being identified as a victim, a person may not be eligible for shelter or other forms of aid mandated by statute.

To avoid arresting a victim, law enforcement officers should ensure that they determine which party is the predominant aggressor. Police can help to do so by asking the following:

  1. Who uses threats and intimidation in the relationship?
  2. Does either individual in the relationship isolate their partner?
  3. Who is emotionally abusive (uses degrading names, humiliating comments, etc.)?
  4. How are minimization, blame, and denial being used by the victim and/or the suspect?
  5. Who utilizes the children to get their way in the relationship?
  6. Who has forced sexual contact or used sexual acts as a way to control the other?
  7. Who has control of money and finances or uses them as a way to control the other?
  8. Who utilizes coercion and threats?
  9. Have any threats been carried out or steps taken to carry them out?
  10. Does either party have a history of committing violent crimes?
  11. What does the premise history tell you about calls for service to the residence?
  12. Is there a history of intimate partner violence between the parties?
  13. Is there a physical size difference between the parties?
  14. Does either party have a protection order against them or a history of protection orders against them?
  15. Who appears to be more capable of assaulting the other?
  16. What is the severity of the injuries to the parties?
  17. Did either party utilize self-defense?
  18. Is there potential for violence in the future? If so, by whom?
  19. Which party has access to firearms or other weapons?
  20. What types of injuries do the parties have? Are they offensive or defensive in nature?
  21. Does either party express fear of the other?
  22. Is there evidence from witnesses?[7]

Both the American Bar Association (ABA) and the National Council of Juvenile and Family Court Judges (NCJFCJ) have prepared spreadsheets covering United States domestic violence arrest policies, both of which were last updated in 2014. The ABA resource covers domestic violence arrest policies in all 50 states, as well as Washington, D.C., American Samoa, Northern Mariana Islands, Puerto Rico, and the Virgin Islands, and can be found here. The NCJFCJ resource covers only primary aggressor statutes and therefore does not discuss all 50 states, but does include Guam, and can be found here.

Difficulties in Determining the Predominant Aggressor

Law enforcement officers should be aware of situations that may further complicate the determination of the predominant aggressor. For example, the IACP instructs law enforcement to use the physical size of the parties as one criterion when evaluating the situation, officers may be tempted to minimize claims of domestic violence made by women who are larger than their partner. This may be even more tempting in situations where both parties are claiming that the other is the predominant aggressor.

The legal definition of domestic violence may also increase the difficulty of determining the predominant aggressor. Laws that vaguely or poorly define domestic violence can place victims at a higher risk of arrest. For example, the Croatian Law on Protection against Domestic Violence (LPDV) classifies psychological and economic violence on par with physical violence. One high-ranking police officer explained that psychological violence that merits arrest includes threats and signs that the offender will harm the victim, rather than name-calling. However, many police officers adopted the view that name-calling, cursing, shouting an insults constitute domestic violence. Thus, in some cases, a verbal argument between spouses has resulted in the arrest of both parties.[8]

Additionally, determining which partner is the predominant aggressor may be more difficult when responding to a domestic violence call regarding same-sex partners. One study of dual arrests in the United States found that 26.1% of female same-sex domestic violence cases and 27.3% of male same-sex cases resulted in dual arrests, compared to different-sex cases where the offender was a man (0.8%) and where the offender was a woman (3%).[9] Describing this difficulty, the New York Office for the Prevention of Domestic Violence explained that “the lack of gender disparity often makes primary aggressor determinations more challenging than the statistically established norm of male perpetrator/ female victim within heterosexual domestic violence.”[10]

[1] International Association of Chiefs of Police, Intimate Partner Violence Response Policy and Training Content Guidelines 6 (2017).

[2] Id.

[3] Women Prosecutors Section, National District Attorneys Association, The National Domestic Violence Prosecution Best Practices Guide 19 (2017).

[4] David Hirschel & Lindsay Deveau, The Impact of Primary Aggressor Laws on Single Versus Dual Arrest in Incidents of Intimate Partner Violence, 23 Violence Against Women 1155, 1158 (2016).

[5] Id. at 1162.

[6] Id.

[7] International Association of Chiefs of Police, Intimate Partner Violence Response Policy and Training Content Guidelines 23 (2017).

[8] The Advocates for Human Rights, Autonomous Women’s House Zagreb, & Bulgarian Gender Research Foundation, Implementation of Croatia’s Domestic Violence Legislation: A Human Rights Report 22–23 (2012).

[9] David Herschel et al, Explaining the Prevalence, Context, and Consequences of Dual Arrest in Intimate Partner Cases 87 (Apr. 2007).

[10] Domestic Violence in the Lesbian/Gay/Bisexual/Transgender/Queer Community, Office for the Prevention of Domestic Violence, (last accessed Dec. 13, 2018).