'Shocking injustice' in two murder trials

One of the most shocking injustices in NSW nearly occurred when a man accused of pouring petrol on his wife and then burning her to death was put on trial twice, a judge has been told.

And the tragic circumstances of a husband mourning his dead wife was made "infinitely worse" by the NSW state government's unreasonable prosecution, Margaret Cunneen SC said in the NSW Supreme Court on Friday.

Justice Natalie Adams admitted her initial feeling upon first hearing the crown case, was that "it must have been him".

"She wouldn't have done it to herself," she said, but added her view had significantly changed by the end of the first trial.

Sydney man Kulwinder Singh at his re-trial in 2021 was found not guilty of murdering his wife Parwinder Kaur at their Rouse Hill home in 2013.

He told police he had been upstairs packing clothes when he heard her screaming.

Ms Cunneen, who represented Mr Singh at trial, said in the face of all the evidence the Crown approached the case with an intractable blind spot.

Ms Kaur was under enormous pressure from family and set herself on fire as a cry for help, but made several miscalculations with tragic results far beyond what she expected, Ms Cunneen submitted.

Mr Singh is applying for his legal costs of both trials to be paid for by the state government.

Justice Adams highlighted forensic issues in the first trial including a 10-minute gap between when the petrol was poured, and when the woman was set alight.

The case was originally presented as all having "happened at once," she said.

Another problem is "while she is sitting there covered in petrol," Ms Kaur makes a reasonably calm call to her brother, and then dials triple zero saying her husband has just tried to kill her.

The defence submitted this was to ensure there was medical assistance on hand, with Ms Kaur underestimating the flammability of her clothes and the substance used.

She had just been watching the Indian Film Gadar in which a woman runs through flames and ends up in a hospital bed with her family on one side, her husband on the other, hair in tact, the court was told.

"The Crown always knew ... there was an effort to preserve her hair," Ms Cunneen said.

"A murderer wouldn't do it nor would a suicidal person."

And no forensic evidence connected Mr Singh with the scene of the alleged crime.

Ten of Ms Kaur's fingerprints were found on the petrol tin, but none of her husband's, while only her fingerprint was found on the lighter as well as only her DNA.

Mr Singh told police he never entered the laundry where the petrol was poured.

"It would be a very brave person to confidently assert they never go into the laundry where they have just murdered their spouse," Ms Cunneen said.

"This was nearly a shocking injustice, one that could hardly be eclipsed in the history of law in NSW," Ms Cunneen said.

Amanpreet Kaur - who is married to Ms Kaur's brother - testified her sister-in-law would never have set herself alight, saying Mr Singh threatened to "vanish" or "kill" his wife.

Mr Singh had regularly argued with his wife to contribute financially, who without his knowledge had $15,000 in her bank account by the time of her death.

But at trial it was made out that she was keeping money aside due to his controlling ways.

"It is open to infer that the grieving family fabricated some evidence and that some of them advanced a theory that the deceased had to squirrel her money away," Justice Adams said.

"What would now be considered coercive control which in fact was going all to her, (it) puts a very different gloss on the relationship."

Prosecutor Philip Hogan said the combination of factors meant they were capable of reasonably founding a circumstantial case to put before a jury.

Justice Adams accepted intense family pressure and unwillingness to accept this was a cry for help weighed on the Crown's decision.

The judge has reserved her decision for a later date.

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