How justification works
New York calls self-defense justification. Once the evidence raises it, the prosecution must disprove it beyond a reasonable doubt. The rules differ depending on whether ordinary physical force or deadly physical force was used, and for deadly force there can be a duty to retreat when that can be done safely, with exceptions such as being in your own home. Being the initial aggressor usually limits the defense, although a person who clearly withdraws may regain it. The analysis looks at what the person believed at the moment and whether that belief was reasonable.
Evidence that supports it
Injuries you suffered, photographs, medical records, video, and witness accounts can show who started the fight and how it escalated. Earlier threats or messages from the other person may be relevant, and in some situations what you knew about the other person's history may matter, though admissibility depends on the circumstances. Do not explain your self-defense claim to police without counsel; even an accurate account can come out incomplete or be misunderstood when given under stress. Keep any messages from the other person, and do not respond to them.
Planning the defense
Self-defense often shapes the entire case, from release arguments to grand jury testimony to trial. In some cases, presenting the evidence early can influence charging decisions, although that choice carries risks and is made case by case. If you hold a license or are not a citizen, raise it early, since the charge level can matter beyond the case itself. In a first meeting we review the incident, the injuries on both sides, the available video, and whether testifying before a grand jury should be considered.
