Ms Chen's body was found 16 months after her disappearance in a stream. Photo / Supplied
Cissy Chen's brother said his heart was broken after the jury delivered the not-guilty verdict today.
Outside court he said he did not want the case reopened because he believed there was no one else with the opportunity or motive to kill his sister.
"For all of our family members we feel very very disappointed and can't accept this result. This result is very unfair to my sister," Mr Chen said.
The outcome would be especially painful for their 80-year-old father in China.
"The pain to him has been beyond description," he said.
Mr Chen said the crime had been committed by a "cold-blooded murderer", who had affected the Chen family for many generations to come.
The pain was exacerbated by the fact only 70 per cent of Ms Chen's remains had been found, he said.
The police refused to comment on the matter outside court and said no decision had yet been made on whether the case would be reopened.
Earlier today Cissy Chen's partner was found not guilty of her murder.
Yun Qing 'Jack' Liu, 58, was acquitted of killing the 45-year-old accountant, who went missing on November 5, 2012.
Ms Chen's body was found 16 months after her disappearance in a stream in a reserve in Totaravale, 11km from their home.
Late this afternoon, the jury returned the verdict as Ms Chen's two brothers - who flew in from China - watched on.
Liu's lawyer Michael Kan told the jury in his closing address the Crown could not prove where, when, how or why the victim was killed, beyond reasonable doubt.
The jury agreed.
Liu's legal team rejected any notion of a rift between their client and Ms Chen and pointed to the evidence of multiple witnesses.
Of particular significance was the testimony of the defendant's son Lia-Li Liu who spent the afternoon with the couple the day before Ms Chen went missing.
He told the court they had a huge banquet, followed by a game of table tennis.
When questioned about the strength of their relationship, he told the court he was happy his father had met someone who understood him and laughed at his jokes.
The evidence stood in stark contrast with that of one of Ms Chen's brothers, Peter, who said he had spoken to his sister that night about "a fierce argument" that took place during the get-together.
Mr Kan was quick to point out holes in the Crown case, which he likened to a castle built on sand.
An injury to Liu's right thumb was highlighted by prosecutors as something that likely came from a struggle when he attacked his partner, rather than from moving a pot plant as he told police.
But defence counsel said there was nothing to back that up.
Ms Chen was characterised as a feisty woman by those who knew her and it was unlikely Liu would have been unscathed had he assaulted her, they said.
The Crown also used CCTV footage of Liu driving through the North Shore to suggest to the jury he had dumped the body in a reserve - near where they previously lived - during a 33-minute window.
Had the defendant made that journey to dispose of the evidence, Mr Kan said, that timeframe would have been "totally implausible".
Ms Chen's remains were found in dense, muddy bush and the defence said there was no evidence their client had been to such a location when police arrived at his house only minutes after he returned.
When Liu was acquitted by the judge he was "accordingly discharged" and could leave whenever he wanted.
He immediately left the dock and bowed to the judge before leaving the court.
Ms Chen's brother Philip shook his head as the defendant walked away.
Mr Chen's wife sobbed as the court closed, telling prosecutors the result was "unfair".
Up to 30,000 protesters are expected to descend on Parliament on Tuesday.