Neb. Rev. Stat. § 25-1238: Neb. Rev. Stat. § 25-1238

If a witness conceals himself, or in any other manner attempts to avoid being personally served with a subpoena any sheriff or constable, having the subpoena, may use all necessary and proper means to serve the same, and for that purpose may break into any building or other place where the witness is to be found, having first made known his business and demanded admittance.