Neb. Rev. Stat. §§ 77-1509
The county board of equalization may issue process to compel the attendance before it of any person with books, records and papers, if necessary, which process shall be served by the sheriff the same as a summons from the district court, and he shall receive the same fees therefor. Any person who shall fail to respond to such process, or who shall refuse to answer any proper question put to him by the board, shall forfeit the sum of five hundred dollars, to be recovered in a civil action in the name of the county. Witnesses shall receive the same fees as witnesses in the district court to be paid by the person, the valuation of whose property is being investigated, in case the board finds that such person has willfully concealed or undervalued his property; otherwise, by the county.
Neb. Rev. Stat. §§ 77-1509