Murder in the Second Degree (18 U.S.C. Sec. 1111) is a federal crime that applies when a person, with malice aforethought, causes the death of another person. This crime is divided into two types: voluntary manslaughter and involuntary manslaughter. Voluntary manslaughter is a killing that occurs under circumstances of extreme emotional or mental distress, or when carried out in a sudden heat of passion. Involuntary manslaughter is defined as a killing that occurs through criminal negligence, or when the death is caused by the commission of an illegal act not amounting to a felony. In either case, the perpetrator must have the intent to cause serious bodily harm or death, but not the intent to kill. This is what distinguishes murder in the second degree from first degree murder.