Nebraska didn't start recording deaths until 1904 and death info is only released from the state 50 or more years after the person's death and then only to certain relatives. Because of their restrictions, some county genealogical, historical and museums create their own death index.
I'd contact the following:
Elkhorn Valley Museum & Research Center, www.elkhornvalleymuseum.org/?p=Research_Center
Eastern Nebraska Genealogical Society, www.usgennet.org/usa/ne/county/dodge/ENGS.HTM