(1) A person commits the offense of murder in the first degree if the person intentionally or knowingly causes the death of:
(a) More than one person in the same or separate incident;
(b) A law enforcement officer, judge, or prosecutor arising out of the performance of official duties;
(c) A person known by the defendant to be a witness in a criminal prosecution and the killing is related to the person's status as a witness;
(d) A person by a hired killer, in which event both the person hired and the person responsible for hiring the killer shall be punished under this section;
(e) A person while the defendant was imprisoned;
(f) A person from whom the defendant has been restrained, by order of any court, including an ex parte order, from contacting, threatening, or physically abusing pursuant to chapter 586;
(g) A person who is being protected by a police officer ordering the defendant to leave the premises of that protected person pursuant to section 709-906(4), during the effective period of that order;
(h) A person known by the defendant to be a witness in a family court proceeding and the killing is related to the person's status as a witness; or
(i) A person whom the defendant restrained with intent to:
(i) Hold the person for ransom or reward; or
(ii) Use the person as a shield or hostage.
(2) Murder in the first degree is a felony for which the defendant shall be sentenced to imprisonment as provided in section 706-656.