It has been more than 25 years since a grand jury was called for an investigation involving murder other than that of a police officer.
Prosecutor Mark Rhodes says Douglas County investigators have exhausted all avenues in the unsolved case of Rebecca Williams.
Williams was found last June, two weeks after she went missing.
Her family has since pleaded for the killer to come forward.
Rhodes says a grand jury has more power than police or prosecutors to get people to testify.
The juries are commonly called on to determine charges in federal cases, but are rarely used in state court.