Professional Services/Expert Witness Testimony


Unless otherwise indicated, trainings range from 1 hour to multiple days, and tailored to your particular needs. John Hamel also offers standard certification trainings for batterer intervention and child abuse program facilitators. Presentations include use of Power Point slides, informational handouts, audience participation, relevant exercises and Q&A.

  • Domestic Violence:  An Overview of the Latest Research
  • Evidence-Based Assessment and Intervention
  • Domestic Violence and Child Custody
  • The Effects of Domestic Violence and the Battered Woman’s Syndrome
  • Male Victims
  • Law Enforcement Responses:  Mandatory Arrest and Dominant Aggressor Policies
  • Domestic Violence and Substance Abuse
  • Domestic Violence Worldwide and Cross Cultural Issues
  • Domestic Violence in the LGBT Community
  • CEUs A

CEUs Available for LCSWs and MFTs
MLEs Available for Attorneys

ONLINE TRAININGS:  For online courses and CEUs, go to:


John Hamel, Ph.D., LCSW, provides expert witness services and case consultation on a variety of issues and topics related to domestic violence and psychological trauma.  He draws upon a broad knowledge of domestic violence research, including numerous original studies in the areas of treatment effectiveness and law enforcement responses, as well as twenty years of experience working with perpetrators and victims of family violence.

Dr. Hamel has worked with prosecutors as well as defense attorneys, in both family law and criminal cases, as well as civil tort cases.  His areas of expertise include the following:

  • Advantages and limitations of Battered Women’s Defense
  • The impact of domestic violence on children
  • Domestic violence and parental alienation
  • Flaws in domestic violence arrest and prosecution policies
  • Differences and similarities between male-perpetrated and female- perpetrated domestic violence


Understanding intimate partner violence and intimate partner homicide:  A research guide for prosecutors and defense attorneys

In the best interests of children: What family law attorneys should know about domestic violence


July, 2019

People v. Gonzales.  Testified on behalf of a woman in Marin County, California, who was facing a six-month jail sentence for failing to complete a court-mandated domestic violence perpetrator program, due to circumstances beyond her control. The jail sentence was dropped. The defense attorney was Jonathan Pickett.

June, 2019

People v Mazurkewicz.  The client was arrested on a domestic violence charge in West Hollywood, CA, and I consulted with his attorney, Sara Caplan. The client was able to secure a satisfactory plea bargain, on reduced charges.

April – May, 2019
Marriage of Garcia.  I consulted with Marcus Morales, an attorney in Santa Barbara, CA, who represented a woman involved in a disputed child custody case, in which there were accusations of domestic violence.

September, 2018 – April, 2019

State v. Ellis.  Provided consultation to Idaho attorney Travis Rice on a domestic violence case. The defendant, a male, pled guilty rather than go to trial.

March, 2019

Ramos v. Harris & Sutphen. Consulted with Attorney Landon Little on a tort case in Nevada County, CA, involving a child custody dispute.

February – March, 2019

State v. McCalop. DeKalb County, GA. The prosecutor’s office hired me to provide expert court testimony in this murder case. Attorneys for the defendant, a woman, hired an expert who argued that she suffered from battered person syndrome, and I assisted the prosecution in showing why such a defense was irrelevant in this case. The defendant was found guilty and sentenced to life in prison.

February, 2019

People v. Vieira. I consulted with Santa Cruz attorney T.J. Brewer on behalf of a woman arrested and charge with domestic violence on her elderly husband. In my report, I concluded that the defendant’s behavior did not warrant a criminal conviction, but should have been handled as deferred prosecution.

October – December, 2018

People v. Mustafa. Provided expert consultation to Hayward, CA attorney Guy Louie, defense attorney for a man who was charged with a domestic violence offense.

September, 2018

Sharp v. Sharp. Contra Costa County, CA. Provided consultation for the mother in a family law case involving allegations of domestic violence perpetrated by the father. The parties settled in mediation.

August – September, 2018

Mortensen v. Lichtenwalter. At the request of attorney Rome Rivera, I reviewed a report from another expert witness hired by opposing counsel in this disputed child custody case. I concluded that this report was deeply flawed, based on long-outdated research.

January – October, 2018

People v. Courtney. Sonoma County, CA. The defendant, a woman who was charged with a DUI, claimed to be under emotional duress by the passenger, who had a record of physical and emotional abuse against her. The defendant’s abuse experience was determined to have been a mitigating factor, and she was given a minimum sentence.

December, 2017 – August, 2018

People V. Rothschild. Provided expert witness consultation to attorney Stephen Gallenson in Sonoma County, California, in behalf the defendant. The defendant faced murder charges after having killed his wife in a domestic dispute. The client had previously suffered emotional and physical abuse. The jury agreed that this abuse pattern was relevant, and rendered a verdict of voluntary manslaughter.

May – June, 2018

Cash v. City of Riverside

Testified at a hearing on behalf of a police officer who pled guilty of a domestic violence charge and was consequently fired from his department. There was strong evidence that his intimate partner was in fact the dominant aggressor in the relationship.

January – March, 2018

Rogers v. Lee. A civil tort case involving emotional distress and PTSD. I worked with Sonoma County Ronald Turan for the plaintiff. A settlement was arrived at by the parties prior to trial.

February – March, 2018

Brown v. Braun. A disputed child custody case. I provided expert witness consultation on behalf of the father, whose parental visits had been curtailed after he’d been accused of domestic violence. Following my report, the restraining order was dropped and father was given joint custody.

August, 2017

State of Georgia v. Rickman. Provided expert witness consultation to Sharla Jackson of the Prosecuting Attorneys’ Council of Georgia, in the case of. The defendant was charged with the murder of her boyfriend, and found guilty in a jury trial.


“Having worked as an Adjunct Professor a the University of San Francisco for the past 22 years, and valuing quality continuing education to enhance my skill base as a professor as well as a therapist, I highly recommend John Hamel’s training. I was so impressed with his material that I have implemented his book as the textbook for the USF Spousal and Partner Abuse course. John’s state-of-the-art material was well organized and professionally presented.”

 – Tanda Ainsworth, MFT, University of San Francisco, School of Education

“John, I wish to commend you for a professional, well-researched, broad-based, in-depth and challenging domestic violence training. Thank you!”

 – Douglas L. Marum, Ph.D., MFT, Certified Batterer Intervention Provider, Private Practice, Napa, CA

“Training by John Hamel is enlightening. His years of experience paired with cutting edge research creates a progressive program that gives hope to the ideal of rehabilitation. I will continue to reference this training for years to come in my professional life.”

 – Allison Vickery, MA, San Francisco, CA