Neb. Rev. Stat. §§ 84-1111
In the event that any obligated officer is or becomes unavailable after an attack, the alternate who is highest on the order of succession among those appointed to succeed him, and who is duly qualified therefor and is available, shall forthwith assume the powers and duties of his office. Any such acting officer shall continue to serve as such until the expiration of the then current term of the officer concerned, but not after the officer himself or a qualified successor thereto becomes available and resumes or assumes the office. The subsequent availability of an alternate who was higher than him on the order of succession, but was unavailable when he assumed the powers and duties of the office, shall not terminate or affect his right to continue as acting officer; Provided, that if an alternate who was not a deputy in the same office at the time of his appointment becomes acting officer, any higher-ranking alternate who was such a deputy, and who later becomes available, shall become acting officer in his stead.
Neb. Rev. Stat. §§ 84-1111