Neb. Rev. Stat. § 44-6405

Uninsured motor vehicle shall mean a motor vehicle with respect to the ownership, operation, maintenance, or use of which: (1) There is no bodily injury liability insurance or bond applicable at the time of the accident; (2) There is bodily injury liability insurance or a bond applicable at the time of the accident but the insurer writing such insurance or bond (a) denies coverage or (b) is or becomes insolvent as described in section 44-2403 within four years after the time of the accident which occurred while the named insured's uninsured motorist coverage was in effect; (3) The owner or operator is unknown and bodily injury, sickness, disease, or death of an insured results from actual physical contact between such motor vehicle and the insured or a motor vehicle occupied by the insured; or (4) The owner or operator is unknown and bodily injury, sickness, disease, or death of an insured is caused by such motor vehicle without actual physical contact between such motor vehicle and the insured or a motor vehicle occupied by the insured if (a) the accident has been reported, as required by law, to the proper law enforcement authorities and (b) the facts of the accident can be corroborated by competent evidence provided by an independent and disinterested person and not by the insured or any person occupying the insured motor vehicle.