The 17-year-old was caged in January this year for brutally murdering the OAP with a hammer, a screwdriver and his own walking stick.
He can’t be named due to legislation protecting the identity of criminals under the age of 18
The thug is too young to be locked up in a prison or Young Offenders Institute, so is serving his sentence at Kibble Care and Education Centre.
He battered a 14-year-old boy on June 13 this year – then attacked two members of staff two weeks later, after taking LSD he’d been sent as a birthday present.
The details emerged today when the youngster appeared in the dock at Paisley Sheriff Court.
Procurator Fiscal Depute Sobia Kidd said the boy and his victim were sitting on opposite couches having a conversation when the red mist descended.
The prosecutor explained: “The boy replied, ‘how long has your dad been dead?’.
“He took exception to that, leapt from the settee towards him and began to punch him to his head repeatedly.
“He then jumped on to the victim’s back and continued to punch him to the head and face.
“Staff had to intervene and separate them both and restrain the accused from assaulting the witness any further.”
In the early hours of June 26 staff were radioed to attend “an ongoing incident” in an area within the centre.
Miss Kidd explained: “The accused had received a birthday card and told staff it contained acid.”
The accused stated he had consumed the acid and was, as such, ‘off his nut’.
“They made attempts to engage him in conversation, but he continued to shout and swear and made attempts to exit the room, repeating, ‘I’m in for murder’.”
He then punched worker Andrew Stevenston on the right side of his face, causing his head to hit the door frame, and “continued to lash out” – also striking worker Allan Scott on the head.
The police were contacted and, when they arrived, found staff restraining the youngster and saw him shouting, ‘I’m in for murder, I’m off my nut’ over and over.
Officers also had to apply a spit hood due to him spitting repeatedly.
Defence solicitor Manus Tolland said that, had his client not been serving a life sentence for murder, he hoped he may have been spared jail for the latest offences.
He said: “He clearly overreacted to the comment about his father.
“It was nine years ago.
“This was only a couple of months after his conviction for this murder.
“There were a lot of things going on in this young man’s mind, such as where his future was going.”
Sheriff Sukhwinder Gill said her “hands” were “tied” because of his 13-year murder sentence, and sentenced him to eight months behind bars, reduced from 12 as he admitted his guilt.
The sentence was backdated to October 8, when the boy was first remanded in custody over the case, and he spoke only to say “cheers” as he was led away in handcuffs.
The High Court in Edinburgh heard that the boy and two pals attacked Alasdair Forsyth, 67, at the flat where he lived alone in the city.
He sustained extensive rib fractures amongst and an array of other injuries during the attack, which one of the other killers said was committed because: “We were all just out our nut.”
Judge Lord Uist slammed the trio at the High Court: “Mr Forsyth suffered the most terrible injuries.
He sustained a total of 80 injuries and died of blunt force chest trauma.
“It is a scandal in a supposedly civilised society that a man should meet his death in this manner.
“The attack on Mr Forsyth was a planned robbery in which each of you took a tool to be used as a weapon, namely a screwdriver, a wrench and a hammer, and battered him to death in his home.”