Caseloads, retirements, unit changes and limited budgets can push older cases down the priority list, even when nobody intends neglect.
Log the date, person, question and response for every contact, and put important requests and update requests in writing.
Often you can request some records under state public records law, though agencies may withhold material connected to open investigations.
It cannot guarantee action, but well-sourced public reporting can encourage file reviews, family meetings and decisions to retest evidence.
State cold case units, prosecutors' victim advocates, attorneys, NamUs and qualified private investigators can all provide additional routes forward.