Prosecutor Bill Thompson said the plea agreement reached this week with David Stone of Moscow may help authorities get more answers, including where Rachael Anderson's body is.
She went missing in April of 2010 after filing for divorce from her estranged husband Charles Capone. He's charged with first degree murder, with his trial set for March.
But Stone, his alleged accomplice, is now testifying against Capone for a lesser sentence. Investigators said they didn't find any remains while searching the Snake River last month.