The difference between voluntary and involuntary manslaughter is fairly self-evident. Voluntary manslaughter means that a person intended to kill or at least cause significant harm. Involuntary manslaughter involves reckless or negligent behavior, but any death that resulted was an accident.
Even if a defendant is guilty of voluntary manslaughter, there are defenses that a criminal defense attorney can make to the court, such as showing that the death was accidental, to try to get the charge reduced to involuntary manslaughter. Which defense strategy is used will depend upon the facts of the case.