A former Tyrone GAA star who shot dead his father is appealing his sentence, it has emerged.
Lawyers for Sean Hackett claim his 10-year prison term is unduly excessive and does not adequately reflect his mental state at the time he carried out the killing.
It is understood that further medical evidence may be brought before the court.
The teenager killed his 60-year-old father Aloysius after shooting him twice in the head outside the family home near Augher in January 2013.
Earlier this year a jury acquitted Hackett of murder, instead convicting him of manslaughter on the grounds of diminished responsibility.
In April a judge sentenced the 19-year-old to life imprisonment with a minimum term of 10 years before he is considered for parole.
However, Hackett's legal team have confirmed they will appeal the sentence. His solicitor Adrian O'Kane said he expected the case to come before the Court of Appeal in the autumn.
"We are appealing against the sentence of life imprisonment with a 10-year tariff.
"The basic grounds of appeal will argue on the part of the defendant that the sentence was excessive and did not adequately take into account the defendant's mental state at the time of the killing."
Mr Hackett, a former chairman of Augher St Macartan's GAC, was shot dead at his home on Aghindarragh Road on January 4, 2013. His son, a former captain of the Tyrone Minor GAA team, admitted carrying out the shooting.
He admitted that he intended to kill his father, but consistently denied murder.
In March a jury accepted defence arguments that Hackett had been mentally ill when he shot his father, and found him guilty of the lesser offence of manslaughter.
The trial heard Hackett had suffered depression in the months before he killed his father, triggered by a split from his girlfriend.
In October 2012 he attempted to strangle his mother Eilish with an electrical cable.
He later told his mother that he believed killing one of his parents would provide him with a guardian-type figure in Heaven.