Neb. Rev. Stat. §§ 76-228
If the grantor dies before acknowledgment, or if for any cause his attendance cannot be procured in order to make the same, or, having appeared, he refused to acknowledge it, proof of the execution and delivery of the deed may be made by any competent subscribing witness thereto before any officer authorized to take the acknowledgment. The witness must state, upon oath, his own place of residence, that he set his name to the deed as a witness, that he knew the grantor in such deed, and saw him sign or heard him acknowledge he had signed the same. Such proof shall not be taken unless the officer is personally acquainted with such subscribing witness, or has satisfactory evidence that he is the same person who was a subscribing witness to such deed.
Neb. Rev. Stat. §§ 76-228