Neb. Rev. Stat. §§ 29-411
In executing a warrant for the arrest of a person charged with an offense, or a search warrant, or when authorized to make an arrest for a felony without a warrant, the officer may break open any outer or inner door or window of a dwelling house or other building, if, after notice of his office and purpose, he is refused admittance; or without giving notice of his authority and purpose, if the judge or magistrate issuing a search warrant has inserted a direction therein that the officer executing it shall not be required to give such notice, but the political subdivision from which such officer is elected or appointed shall be liable for all damages to the property in gaining admission. The judge or magistrate may so direct only upon proof under oath, to his satisfaction that the property sought may be easily or quickly destroyed or disposed of, or that danger to the life or limb of the officer or another may result, if such notice be given; but this section is not intended to authorize any officer executing a search warrant to enter any house or building not described in the warrant.
Neb. Rev. Stat. §§ 29-411