Neb. Rev. Stat. § 43-146.10

If an adopted person twenty-one years of age or older, after following the procedures set forth in sections 43-146.04 and 43-146.05 , is unable to obtain information about the adopted person's relatives and there is no unrevoked nonconsent form as provided in section 43-146.06 on file with the department, such person may then contact the child placement agency which handled the adoption or the department.