Justice has "finally been done" for teenager Daniel McAnaspie and he can "rest in peace now", his family said after a man was jailed for 13 years over his killing.
Daniel's sister, Caitriona McAnaspie, was speaking after Trevor Noone (29) was sentenced at the Central Criminal Court, where he pleaded guilty to manslaughter.
A co-accused, Richard Dekker (30), had already been jailed for life after being found guilty of Daniel's murder by a jury.
"I'd like to thank everyone for their support over the last few years and especially the last couple of weeks," Caitriona said outside court. "My brother can rest in peace now.
"We did seven years of trying to get justice for Daniel and [Noone] showed no remorse whatsoever, and he never apologised either."
Another sister, Nikita, said: "He was a lovely young fella. He didn't deserve to die the way he did and them two absolute scumbags are going to rot in hell."
Caitriona added: Earlier, gardai had to intervene in angry clashes between supporters of the accused and the victim inside the court building.
Applause had erupted in the courtroom when Mr Justice Patrick McCarthy passed sentence on Noone, who did not react.
Daniel (17) was killed at Tolka Valley Park on February 26, 2010. His decomposed body was found almost three months later in a drain in Co Meath. He had been stabbed multiple times.
Dekker and Noone, both from the Blanchardstown area, became suspects in the disappearance because they were known to have been with Daniel the evening he went missing.
Daniel, an orphan who had been in the care of the HSE, had skipped curfew and spent the evening with Dekker, Noone and three other friends.
At around 4am, Daniel's friends went home, but he remained with Dekker and Noone. The men denied knowing what happened to Daniel, but after his remains were found they each blamed the other for stabbing him with garden shears and hiding his body.
Throughout garda interviews, Noone had blamed Dekker for the killing.
He also admitted he knew Dekker was carrying a blade and wanted to stab Daniel. Sentencing Noone, Judge McCarthy said what happened was "quite horrific in nature".
He said one only had to mention the garden shears as a weapon to realise "how grave" the effect was.
He said Daniel was placed in a suitcase after Noone had got into it to "measure the size".
The body was then brought to a location in Co Meath and dropped into a drain.
"Mr McAnaspie did nothing whatsoever to deserve this," Judge McCarthy said.
Noone had said of his co-accused: "He said he was going to stab him."
The judge said this showed Noone's "level of moral culpability".
Referring to a psychological report, he said it stated Noone had "cognitive difficulty" and what was described a "schizoid personality".
Judge McCarthy said that, unlike his co-accused, Noone had shown remorse. The main factors in mitigation were this remorse and his plea of guilty, the judge added.