Human beings killing one another has been an unfortunate constant throughout our history. With the onset of civilization, trying to curb needless and wrongful death has been one of the greatest challenges for lawmakers. In this article, we'll look at the legal definition of homicide and the crimes that fall under this category.

What Is Homicide?

Homicide is defined as the killing of one human being by another. While this definition may seem straightforward, there can be a lot of variation in the circumstances surrounding a homicide. For instance, two men could get into a fistfight in which one man dies as a result of his injuries. In this case, the death would be considered a homicide. However, if the same men got into a fistfight and one of them died due to an unrelated medical condition, the death would not be classified as a homicide.

Therefore, different types of homicide offenses are categorized based on the circumstances surrounding the killing and the intent of the person who committed the act. The three main types are murder, manslaughter, and lawful killing.

Type 1: Murder

Murder is the most severe kind of homicide. It is defined as the intentional killing of another person with malice aforethought - i.e., the specific intent to kill someone. The most straightforward example of murder represents a person who shoots another person in the head with the intent to kill them - an element of crime called “mens rea.”

Therefore, if your question was: “What is the difference between murder and homicide?” the answer is that murder is a subtype of homicide. Murder is the most serious of homicide offenses and is punishable by long-term imprisonment, life in prison, or even the death penalty. In contrast, homicide simply refers to the act of killing a person, which can be either unlawful or lawful.

All murder charges fall into one of two categories: First-degree and second-degree murders. People asking “What is first-degree homicide” are actually asking about first-degree murder, or “aggravated murder.” This kind of killing is willful and usually includes planning. It can be anything from stalking someone before murdering them to felony murder. Someone charged with first-degree murder can be sentenced to either long-term imprisonment, life in prison, or even death. In some states, a person convicted of first-degree murder is automatically sentenced to life in prison without the possibility of parole, or the death penalty.

Second-degree murder is an unlawful killing that is not premeditated or otherwise planned, but was committed with the intent to kill. It is often a result of “the heat of the moment,” by a person whose judgment is affected by the circumstances, but who has a clear understanding of the outcome of their actions. As there are different types of murders, the punishments vary. Second-degree murder is usually punished by long-term imprisonment.

We should also mention that three US states, Florida, Pennsylvania, and Minnesota, recognize the least severe form of murder - third-degree murder. In this case, the killing is committed without planning but with the intent to cause serious bodily harm.

Finally, let’s not forget that criminal law also differentiates between a double and triple homicide. As the name suggests, double homicide is killing two people; triple homicide is the killing of three people. Homicide with more than three consecutive victims is serial murder, and homicide with more than three simultaneous victims constitutes mass murder. These types of homicide are typically handled differently than single homicide cases, as they involve multiple victims. Those accused of causing the deaths of two or three people will typically be charged with two or three counts of homicide instead of a single charge combining the deaths.

Type 2: Manslaughter

If you've ever binge-watched a crime drama or two, you're probably familiar with the term “manslaughter.” But what exactly is it? When speaking about the different types of homicide, we should make a clear distinction: Unlike murder, which is always intentional, manslaughter is often the result of accidents or negligence.

For example, if someone gets into a fistfight and unintentionally kills their opponent, they could be charged with manslaughter. Or, if someone runs a red light and causes a fatal car accident, they could also be charged with manslaughter. Essentially, manslaughter is any killing that hasn’t been planned or intended, but results from someone's careless actions. While the penalties for manslaughter can vary depending on the circumstances, it is typically punished by a lengthy prison sentence.

There are two main types of manslaughter: Voluntary and involuntary. Namely, involuntary manslaughter occurs when the death is caused by an act that was negligent or reckless, such as driving under the influence of drugs or alcohol (i.e., vehicular manslaughter). The offender did not want his victim to die but caused their death accidentally.

Voluntary manslaughter, on the other hand, occurs when the death is caused by an action that was not premeditated, such as during a fight. If you’re still unclear about what this type of homicide is, here’s an example: If someone catches their spouse cheating and then kills them accidentally through intentional violent action, that would be considered voluntary manslaughter.

Lawful Killing

In the United States, a "lawful excuse" is a legal defense to a criminal charge. Essentially, it means that the defendant had a legally valid reason for killing someone else. Depending on the state law and homicide definition, many lawful excuses can be raised in court; the most common include self-defense, necessity, defense of infancy, mental disorder, and duress.

Self-defense is probably the best-known lawful excuse for homicide. If someone reasonably believes that they are in danger of being harmed, they may use force to protect themselves. However, there are limits to how much force can be used in self-defense, and defendants must be able to show that their actions were truly necessary to prevent harm.

Necessity is another common lawful excuse that can tell us what justifiable homicide is. This defense applies when the defendant has no other reasonable choice but to break the law to prevent greater harm. For example, imagine driving down the highway and seeing a car accident. If you pull over to help, you may be breaking the law by obstructing traffic. However, you would likely be able to use the defense of necessity, as you had no other reasonable choice but to help.

As there are multiple types of murders, there are just as many lawful excuses defendants rely on: Defense of infancy precludes prosecution for defendants under the age of 7, and prosecution as adults for children aged 7 to 14. Essentially, it means that these defendants cannot be culpable for their actions because they do not have the mental capacity to understand them.

Mental illness is another common excuse raised in court. If a defendant can prove that they have a mental illness preventing them from comprehending the gravity of their actions, they may be able to avoid conviction. Depending on its severity, mental illness can impair a person's ability to understand their actions or make rational decisions.

Finally, the explanations of homicide and its definition often include the duress defense, a lawful excuse used when the defendant was threatened or coerced into breaking the law. For example, if someone is kidnapped and forced to rob a bank, they may have committed a crime under duress. However, the defense is not available if the defendant could have reasonably avoided the threat or if they willingly took part in the crime.


What is the difference between homicide and genocide? When an organization of any kind - be it a company, country, or terrorist organization - commits crime with the intent of eliminating communities based on a specific characteristic, it is referred to as genocide; homicide means killing a person with or without intent.

As the UN defines it, genocide means any of the following acts committed with the intent to destroy, in whole or in part, a national, ethnical, racial, or religious group, as such:

  • Killing members of the group;
  • Causing serious bodily or mental harm to members of the group;
  • Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;
  • Imposing measures intended to prevent births within the group;
  • Forcibly transferring children of the group to another group.

As you can see, genocides can be committed through various means and aren’t limited to measures we usually associate with them (e.g., WW2 gas chambers); instead, they can be executed through the systemic deprivation of necessary resources for specific regions or communities. The most notorious examples include the Holocaust, the Holodomor, the Khmer Rouge regime killings in Cambodia, the Armenian genocide at the hands of the Ottoman Empire, and the Rwandan genocide.

Therefore, the meaning of homicide is much broader than that of genocide.

Homicide Investigations

Homicide cases are investigated by the police and prosecuted by the local, state, or federal government. Homicide cases often require the expertise of many criminal law professionals, both on the policing and prosecution front. The most important person in a homicide investigation is the detective, who is usually responsible for leading the process. Regular police officers and forensic technicians typically assist detectives.

All in all, homicides are among the most severe crimes people can commit in modern society. Aside from the loss of life it causes, it also has devastating consequences for the victim’s family and social circle, both in emotional and material terms. However, as we can see, not all homicides are equal in the eyes of the law, and some can even be considered “justified,” at least on a legal level.