A jury convicted 19-year-old Ryan Hare last month of first-degree murder in the death of 18-year-old Matthew Silliman. He's now serving a life sentence.
Police implicated three other teens in Silliman's death.
Police also orginally charged 19-year-old Aadil Khan with first-degree murder, but Kahn later made a plea deal to testify against Hare. He pleaded guilty to two counts of conspiracy, attempted murder and second-degree murder.
But Khan never testified and prosecutors asked a judge to scrap the deal, saying Kahn was no longer cooperating.
In his ruling Tuesday, Superior Court Judge Paul Ridgeway said "the state must prove by a preponderance of evidence that the defendant breached a material term of the agreement," and the state failed to do that.
Hare's girlfriend, 19-year-old Allegra Dahlquist, also made a plea deal and did testify against Hare. She has not been sentenced yet for pleading guilty to two counts of conspiracy, attempted murder and second-degree murder.
The fourth defendant, 18-year-old Drew Logan Shaw, has not gone to trial. Like Dahlquist, Shaw testified against Hare. However, he does not have a plea deal and his trial date has not been set.
Khan's sentencing has been set for November 1.