The teenager sentenced to one year for killing his grandfather is to be released at the end of November.
Eamonn Coyle, 18, was sentenced on 1 November. He will be released from Hydebank Young Offenders centre.
Coyle served 10 months in Woodlands juvenile justice centre from April 2009 to Feb 2010. He was then bailed but was returned to custody in October 2010.
It has been revealed that the Director of the Public Prosecution Service (PPS) is to consider his sentence.
The PPS has 28 days to decide if they will refer the case to the Court of Appeal if they believe it is "unduly lenient".
Coyle was 16 when he strangled and stabbed his grandfather, Francis O'Neill, at his home in Omagh.
The chair of the Justice Committee at Stormont had criticised the 12-month sentence handed down and said it should be reviewed.
Lord Morrow said the sentence sent out the wrong type of message.
"I think the public would fail to understand the judge's rationale behind this decision and I think he has some more explaining to do," he said.
In sentencing, the judge said there were mitigating factors in terms of why Coyle had been sentenced to a year's detention and two years on licence.
No future risk
The judge said he was certain Coyle did not intend to kill his grandfather, or even to seriously harm him, but that he had gone to his home "for the motive of theft or robbery".
Mr Justice McLaughlin said he accepted Coyle posed no future risk to the public.
He also said that he would recommend to the justice Department that while on licence Coyle undertakes a life skills and educational course and that his movements and associates be closely monitored.
Lord Morrow said he was shocked and did not think a 12-month sentence for manslaughter was appropriate.
"People can't understand it, this could be reduced to six-months, he said.
During the trial Coyle's mother Mrs Rose Colton said since the killing, he was a changed person, adding "Eamonn is my son and I'm standing by him".
His aunt Mrs Mary Kelly added that Coyle realised the hurt he'd caused, and that he will regret and live with that for the rest of his life.
Lord Morrow said although it was significant Coyle's mother had stood by him, he still thought the case should be reviewed.
"I'm not sure people are convinced justice has been delivered, irrespective of what the circumstances were and what the family might have said."
"An elderly man is in his grave as a result of this and we should never lose sight of that."
In a statement, the Department of Justice said: "Sentencing in the individual case is a matter for the judiciary.
"Last month the justice minister launched a consultation on a sentencing guidelines mechanism which considers a range of issues impacting on confidence in sentencing and seeks views on what role a sentencing guidelines mechanism might have in addressing them."