The family of a man who was killed on New Year's Day have had their bid for an appeal of his attacker's jail sentence refused.
Shaun Woodburn's family say the four-year sentence handed to his teenage killer last month "does not represent justice".
A petition for an appeal of the sentence has gathered more than 65,000 signatures.
Crown Office lawyers have decided there will be no appeal, saying the sentence did not meet the legal requirement of being "unduly lenient".
Mr Woodburn's father Kevin updated supporters on Twitter.
He said: "The Crown and lord advocate have denied us our appeal against the joke sentence passed on our son's killer.
"I thank all of you that have signed our petition and we are truly grateful to you all. However we will not stop, our fight continues."
Mr Woodburn, 30, died after he was attacked by a teenager in the early hours of January 1 in Leith, Edinburgh.
The former Bonnyrigg Rose FC player died after suffering massive head injuries.
The teenager, who is now 17 and cannot be named because of his age, was jailed for four years after a jury returned a verdict of culpable homicide.
He had committed several other assaults during the night along with his friend Mohammed Zakariyah, targeting innocent members of the public at random.
A Crown Office spokesman said the teenager was originally indicted for murder but a jury returned a verdict of culpable homicide.
The spokesman said: "In light of the jury's verdict, the issue of whether the sentence was unduly lenient required to be addressed on the basis that the death of Mr Woodburn was caused by a single punch which caused him to fall to the ground sustaining a fatal injury to his head.
"The accused was 16 years old at the time of the offence and had no previous convictions."
He continued: "The Crown can proceed with an appeal that the sentence is unduly lenient only where the relevant test is met, namely, whether the sentence falls outside the range of sentences that a judge applying his or her mind to all of the relevant factors could reasonably have considered appropriate.
"This criteria is well established in case law.
"In this case, Crown Counsel have concluded that the test for an appeal has not been met and accordingly have decided there will be no appeal against the sentence."
Mr Woodburn's family will be discussing the case with the Crown Office on Tuesday.