But they vowed to ''fight for justice'' for him.
Daniel Ethan Smith, who was then 17, was sentenced by Justice John Fogarty in the High Court at Timaru on June 17, 2011, to life imprisonment with a minimum parole period of 10 years after being convicted of murdering William Lewis (16) on April 1, 2010.
Smith appealed his conviction and his case was heard by the Court of Appeal on September 16. In a decision released yesterday, his murder conviction was quashed. A retrial has been ordered.
Any issue of bail would be dealt with by the High Court and all other details relating to the appeal were suppressed.
William's grandparents, Lyne and Owen Dorsey, of Oamaru, along with other members of the family, sat through the hearings and trial of Smith.
Yesterday, Mrs Dorsey described the family's reaction to a retrial as ''heartbroken'' and ''upset''.
''We are right back to square one with a retrial,'' she said.
''We are just absolutely heartbroken.''
A court suppression order limited what the family could say.
Asked if they would attend any new trial, Mrs Dorsey said that would depend on where the trial was - in 2011 it was in Timaru.
''We will fight for justice for William.
''There is no way I will let my daughter [Jenny Brokenshire] and Peter [Lewis] go through this alone. We have to be there for each other,'' she said, referring to William's mother and father.
The family had not expected the conviction to be quashed.
''We always knew there was a possibility, but we did not expect it,'' she said.
Smith's family could not be located yesterday for comment.
The teenagers got into an altercation on the night of April 1, 2010, and William was allegedly stabbed in the back three times, penetrating both lungs and partly severing his aorta.
William ran a few metres, but collapsed and could not be revived by emergency services.
