Determining the Predominant Aggressor
last updated November 2010

A “predominant aggressor” is defined in the United States as the party who is the most significant or principal aggressor. Police must determine which party is the predominant aggressor in order that the true victim can effectively seek safety, and so that offenders are held accountable.

A violent assault is one act in a series of controlling and intimidating tactics used by a batterer to attain power and control over the victim.  Victims may utilize violence to avert an attack from the aggressor or in self-defense.  Thus, the predominant aggressor may not be the first party to use violence in the incident.  Batterers may try to convince the police that the violence was mutual and that they are also a victim.  If both parties are arrested and charged, there is little possibility that the batterer will be convicted. Research indicates that when mandatory arrest laws are combined with predominant aggressor policies, dual arrests are reduced to 2% of all domestic violence arrests.

In order to identify the predominant aggressor, the police must understand the dynamics of domestic violence Police must identify which injuries are due to self-defense and which are offensive injuries. The police must also look beyond the visual evidence and consider the context of the act of violence by identifying controlling behavior in the predominant aggressor and fear in the victim.  Police must be able to recognize the tactics of power and control.  Some of these tactics are:

  • Emotional abuse
  • Patterns of violence
  • Isolation of victim
  • Use of threats
  • Enforcement of trivial demands

 To determine the predominant aggressor, police must consider:

  • Offensive and defensive injuries
  • The seriousness of injuries received by each party
  • Threats made by a party against the other or a family member or a pet
  • Whether a party acted in self-defense or in the defense of another
  • The height and weight of the parties
  • Which party has the potential to seriously injure the other party
  • Any history of domestic violence between the parties
  • Prior convictions of assault
  • Orders for protection that have been filed by a party
  • Whether a party has a fearful demeanor
  • Whether a party has a controlling demeanor
  • Witness statements

Police must consider whether the injuries and the evidence corroborate the statements made by each party and by witnesses.  Police must be aware of the many strategies victims utilize to reduce the risks to themselves and their children; for example, a victim may strike in anticipation of the aggressor’s violence as a means to prevent a higher level of violence, or to prevent harm to a child or a pet. These considerations will provide the most accurate account of the violent incident and of the total family dynamic. 

The determination of the predominant aggressor, and the reasons for that determination, must be included in the police report. Otherwise, offenders will successfully manipulate the system and victims will not be protected. As a result, victims may not contact police the next time violence occurs.

Police must be able to detect injuries from a batterer who knows how to beat a victim in places where it is hard to identify redness, swelling, or bruises. Police must also be knowledgeable about strangulation, a lethal form of domestic violence where visible injuries may not be immediately apparent. Some US states have implemented additional police training to properly identify and address such cases; strangulation is also a felony in various parts of the country.

If the predominant aggressor is misidentified, there could be important 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 would not be eligible for shelter or other forms of aid mandated by statute.


Alberta Justice Communications, “Domestic Violence Handbook for Police and Crown Prosecutors in Alberta," rev. January 2008,; this handbook also contains a sample police report form.

Beaulier, Maury D., "Minnesota's Felony Assault by Strangulation," January 20, 2010,

Chapter 2 of the National Institute of Justice Report, "Practical Implications of Current Domestic Violence Research: For Law Enforcement, Prosecutors, Judges,"

Chapter 4 of the Toolkit to End Violence Against Women,

Coleman, Soncia, Report to Connecticut General Assembly on Neighboring States' Primary Aggressor Laws, December 11, 2009,

“Domestic Violence Legislation Signed in to Law,” July 25, 2007,

Hirschel, David, Domestic Violence Cases: What Research Shows About Arrest and Dual Arrest Rates at

New York Office for the Prevention of Domestic Violence Bulletin, "Strangulation in Domestic Violence and Sexual Assault."

Roanoke Police Department, “Determining the Primary Aggressor” at

Rogers, John B. and Ziemer, Gretchen, “Identifying Aggressors Brings Context to Crises,” Sunday August 12, 2007,

Strack, Gael B., “She Hit Me, Too,” Identifying the Primary Aggressor:  A Prosecutor’s Perspective at
"Primary Aggressor Chart", Battered Women's Justice Project, compiled by Sandra Murphy and Mary Kathleen Fenske, 2008. This is a 2008 compilation of all state statutes that use “primary” or “predominant” or “principle” aggressor language. Only the portion of the statute that applies to primary aggressor or mutual or dual arrest is cited in this chart. Access the chart here:, and see below example statutes.
US Primary Aggressor Laws
From the Battered Women's Justice Project