Homicide, Murder, and Manslaughter in Illinois

Illinois defense attorney, Illinois criminal lawyer, violent crimeHomicide, murder, and manslaughter are familiar terms, and people often use them somewhat interchangeably to describe killing. But under Illinois law, they actually have different meanings, which can sometimes be confusing.

In Illinois, the term “homicide” means the killing of another person. Murder and manslaughter are types of homicide. Depending on the circumstances, homicide may or may not be a crime. Homicides are considered justifiable if there was a reason to kill the other person, such as self-defense or defending another person. If the homicide was justifiable, it is not a crime. Murder and manslaughter, however, are both criminal offenses in Illinois.


Under Illinois law, murder is killing with malice. The prosecution may show that a defendant had malice by showing that the defendant:

  • Intended to kill or to do great bodily injury to another;
  • Knew that his or her actions would cause death;
  • Knew that his or her actions would cause a high risk of death or great bodily harm; or
  • Was committing or attempting to commit a felony.

Murder is further divided into first and second degree murder. First degree murder means killing without lawful justification and with malice. Generally, first degree murder must be premeditated, unless it was felony murder. Felony murder means causing a death in the course of committing a felony, whether or not the defendant intended to kill anyone.

Second degree murder is not premeditated. It is an intentional, but not planned, killing. It requires proving malice, plus that the defendant either:

  • Acted out of sudden and serious passion, caused by the victim, e.g. walking in on one’s spouse in bed with another person; or
  • Unreasonably believed that the killing was justified, e.g. killing for reasons of self-defense, but killing an unarmed person who did not pose a serious risk of death or great harm.


Manslaughter is the unlawful killing of another person without malice. There are two types of manslaughter in Illinois: voluntary and involuntary.

The crime of voluntary manslaughter was largely replaced by second degree murder, and now only applies to the killing of an unborn child. Voluntary manslaughter is the killing of an unborn child without lawful justification, plus the defendant either:

  • Was seriously provoked by another person, causing a sudden and intense passion, and in trying to kill the provoker, accidentally kills the unborn child; or
  • Unreasonably believes that there exist circumstances to justify the killing.

Involuntary manslaughter is the least severe homicide charge in Illinois. It means the unintentional killing of another person, without lawful justification. A person commits involuntary manslaughter when he or she recklessly acts in a way likely to cause death or serious bodily injury, whether lawfully or unlawfully.

Homicide offenses are extremely serious. If you have been charged with murder or manslaughter, it is essential to have the advice of an attorney. An experienced attorney understands the nuances of the different homicide charges, and may be able to reduce your charges based on exonerating circumstances or possible defenses. Please contact the dedicated Naperville criminal defense attorneys at Law Office of Glenn M. Sowa, LLC for an initial consultation on your case and to learn how we may be of assistance.