They were a family who worked tirelessly over three decades to build up their new lives after fleeing Vietnam 30 years ago.

But their efforts were destroyed with just one punch from 16-year-old John Reid which caused the death of Simon San. The 40-year-old hit his head on the pavement outside the Edinburgh takeaway where he worked after being set upon by a gang of youths.

As a child, Mr San had escaped with the rest of his family from the Communist regime after the US pulled out of South Vietnam.

But yesterday the San family spoke of their agony at losing “a good son and a good brother” who was the main carer for both his elderly parents, who themselves then had to fight for an inquiry into how the police handled the case.

An internal Lothian and Borders Police investigation came after Mr San’s family lodged an official complaint in which they made 39 allegations against the force.

Mr San’s father, Trieu Seng San, wept as he heard through an interpreter his own words being read by his lawyer Aamer Anwar at a press conference held at police headquarters at Fettes.

Mr San was flanked by his daughters Shirley and Candy clutching their brother’s picture.

He said he is convinced his wife will not recover from the tragedy. He said: “Simon’s murder destroyed the whole family.

“Since his death, my wife has been ill and bed-bound.

“It is difficult for me as I now need to face the fact that my wife will be leaving me soon shortly after losing my youngest son.”

He continued: “This is the darkest moment of my life knowing that I am going to be left alone in this house soon.

“My wife’s health was improving after an operation two years ago. Since Simon’s death, her health has been deteriorating.”

Mr San went on to describe deficiencies in the police investigation.

“When the family liaison officer told me my son had died after the assault, I could not express myself because there was no interpreter present,” he said.

“I found out about the media report of my son’s death through my children because I do not read English.

“My children told me that the senior officer said Simon was in the ‘wrong place at the wrong time’, and described it as a minor attack.

“This caused me great distress. I felt the police were implying that my son deserved to die. My son was at his place of work conducting his normal work duties.”

Mr San said that when he was taken to identify his son’s body no interpreter was present.

“We feel very let down and if we had not complained about our treatment, we would have never found out about the mistakes made by the officers,” he added.

“The officers may well be disciplined but for us they have played a role in a lack of justice which we should have been entitled to as a grieving family.

“My son lost his life and I am convinced the accused received a lesser sentence because the officers failed to investigate the racial motivation of this case. The racial motivation was completely denied by the officers despite there being evidence.”

Reid was jailed for five years after admitting the culpable homicide of Chinese-born Mr San.

Among the findings, the inquiry concluded that the force failed to recognise the attack on Mr San was racist and placed little emphasis on racist language used by the youths shortly after the incident.

The inquiry also found that the case should have been declared a “critical incident” by police, but that the incident was described as minor.

It added that the appointment of an untrained officer to a significant post in the investigation “left both the officer and the organisation exposed and at risk”.

Mr Anwar said that had the attack been treated as racially aggravated, he believed the judge could have added several years to the sentence.

Mr Anwar added: “The authorities should not mistake the silence of the Chinese community as a weakness. Simon’s family are part of Scotland’s community and feel betrayed by those who should have given them justice. The police inquiry may be over, but we now expect the Lord Advocate to order an immediate inquiry into their prosecution of this case.”

The Crown Office said: “For a racial aggravation to be proved there must be evidence to demonstrate the motivation for the commission of the crime. There was no evidence in law to support this and this remains the case.”