Neb. Rev. Stat. § 77-1233.02

The county assessor with the aid of his or her deputy and assistants shall carefully examine, check, and verify all taxable tangible personal property tax returns. The assessor may make such investigation, examination, and inspection of the property set out in a return and examine under oath the person making the return as to his or her books, records, and papers in order to enable the assessor to determine that all taxable tangible personal property of the taxpayer is listed for taxation at its net book value.