California Penal Code Section 273.5(a) Domestic Violence
Any person who inflicts corporal injury on another person with whom they have previously had a dating relationship, or on a current or previous cohabitant, that results in a traumatic condition, is guilty of violating California Penal Code section 273.5(a).
i. a traumatic condition results physical forced is used that results in a wound or other bodily injury, whether minor or serious.
ii. the act must have been willful and not in self defense (intentional and on purpose).
iii. a cohabitant is defined as two unrelated persons living together for a substantial period of time, indicating some permanency in the relationship.
The District Attorney must prove beyond a reasonable doubt that all of the above elements are true.
Example Case: A boyfriend and girlfriend are living together and they get into an argument over the contents of a text in girlfriend's phone. The boyfriend get rough by grabbing the girlfriend's arm while yanking her phone at our her hand. She then tries to take the phone back, and boyfriend shoves her hands back while doing so, boyfriend's hand slips and hits the girlfriend in the eye. Bruises are left on both her arm and near her eye. There is no blood, and the bruising is light in color.
Conclusion: Domestic violence has occurred between two unrelated cohabitants. Even though boyfriend did not specifically intend to strike girlfriend, he nevertheless willfully used physical application in such a way that as a natural and probable consequence of his actions, he could expect that injuries may result. The injuries need not be serious. Boyfriend was not acting in self defense.
Example Two: A similar situation as above, but suppose boyfriend was angry but merely questioning girlfriend about the contents of her phone, but girlfriend becomes angry in response to boyfriend's mistrust and she raises her phone up over her head and screams profanities as she brings her hand and phone down aggressively toward boyfriend's head and face. Boyfriend raises his hands to protect against being hit with the phone, but while doing so, he accidentally hit girlfriend in the lip. She is bleeding when the cops show up.
Conclusion: Domestic Violence by boyfriend has not occurred. He was not acting willfully knowing he could inflict injury, but merely attempting to block girlfriend's attack. He was acting in self defense. However, girlfriend is guilty of domestic violence if she hit boyfriend while causing even minor injuries to his hands or arms. She was not acting in self defense.