Woman Who Killed Ex Has Manslaughter Conviction Quashed on Appeal

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By Paul Gregoire and Ugur Nedim

At around 9pm on 13 May 2012, Miguel Silva secretly called the police to report that a man was yelling, screaming and kicking items on Livingstone Road in Marrickville, NSW. Mr Silva didn’t give his name to police, and nor did he mention the man was his sister’s ex-partner.

Mr James Polkinghorne, who was high ice, was across the road from Mr Silva’s parents’ home. He was demanding that Jessica Silva come out of the house. Ms Silva was staying with her parents after having recently separated from Mr Polkinghorne.

Polkinghorne was enraged, as Ms Silva hadn’t returned to his serviced apartment, where she’d spent the night before. During the day, he had made numerous calls and sent text messages threatening violence, which included that he would “cave her face in.”

Ms Silva eventually went out the front of the house, followed by her brother. Mr Polkinghorne raced across the road and punched Ms Silva twice in the face. As a fight broke out between Polkinghorne and her brother, Ms Silva returned to the house to obtain a knife.

In the meantime, Ms Silva’s father, Avalino, went outside and found Polkinghorne straddling his son. The father and son began wrestled with Polkinghorne, who was a large man. Ms Silva then returned to the scene with the knife and stabbed her ex-partner five times. The last wound proved fatal.

Charged with murder

Ms Silva was subsequently charged with murder, under section 18 of the Crimes Act 1900. Section 19A of the Act states that a “person who commits the crime of murder is liable to” life imprisonment. The offence also carries a standard non-parole period (SNPP) of 20 years.

An SNPP is a reference point for the sentencing judge when determining the minimum time a person must spend behind bars, before being eligible to apply for release on parole.

Evidence at trial

Ms Silva pleaded not guilty and the case ultimately proceeded to a jury trial in the NSW Supreme Court, which commenced on 12 November 2014 and ran for eleven days.

During the proceedings, the jury heard that Ms Silva had been in a four year relationship with the deceased, and over that time, she’d been subjected to repeated domestic violence attacks. She told police she hadn’t reported the incidents due to being afraid her partner would kill her.

The content of 80 calls and text messages between Polkinghorne and Silva on the day of the incident were presented to the jury. NSW police had been recording the pair’s communications, as the deceased was suspected of involvement in a murder.

In all of the interactions, Polkinghorne was found to be excessively angry, threatening, and at times, incoherent.

Miguel and Avalino Silva both testified in court. However, there were inconsistencies in their evidence, especially relating to whether Polkinghorne was choking Miguel, whilst he was on top of him in the middle of the road.


Ms Silva’s criminal defence lawyers argued that she’d killed Polkinghorne in self-defence. Section 418 of the Crimes Act provides that a person is not guilty of an offence, “if the person carries out the conduct constituting the offence in self-defence.”

The Act states that a person does so if they believe it is necessary to defend themselves or another, to prevent or terminate unlawful deprivation of liberty, if they’re protecting property, or preventing criminal trespass.

Section 420 states that the defence is not available to a murder charge if the person killed to protect property or prevent a trespass to property.

Section 421 of the Act stipulates that if a person uses force that results in death to defend themselves or another, but their conduct is not reasonable as perceived by them, then they’re not guilty of murder, but they are criminally responsible for manslaughter.

A conviction of manslaughter

On 4 December 2014, the jury found Ms Silva guilty of manslaughter under section 18 of the Crimes Act. The maximum penalty for manslaughter is 25 years in prison and there is no SNPP for the offence.

NSW Supreme Court Justice Clifton Hoeben sentenced Ms Silva to 18 months imprisonment.

However, he suspended the sentence under section 12 of the Crimes (Sentencing Procedure) Act 1999, on the condition she enter into a good behaviour bond.

This meant she did not have to spend time in prison.

The evidence wasn’t there

Ms Silva appealed her manslaughter conviction to the NSW Criminal Court of Appeal (NSWCCA) on 27 June 2016. She did so on the single ground that the verdict was unreasonable and could not be supported by the evidence.

NSWCCA Justice Mark Leeming said, “The single issue presented by this appeal is whether it was open to the jury to be satisfied beyond reasonable doubt that Ms Jessica Silva was guilty of manslaughter.”

Key to this issue was whether the Crown had proven beyond a reasonable doubt that Ms Silva didn’t perceive her response necessary in order to defend herself or her other family members, explained Justice Robert Hulme. And in his Honours’ estimation the prosecution hadn’t.

Justice Hulme pointed out that while there were inconsistencies in the evidence, there were some very clear facts that had been established: Miguel was on the ground, Polkinghorne was on top of him, and Avalino was trying to stop the attacker.

And as the police arrived soon after the killing had occurred, there was no time for those involved to collaborate their stories, the justice reasoned. And also, there was no contention that, prior to the arrival of the officers, Ms Silva was completely unaware that her brother had called the police.

His Honour further asserted that while the jury could reject the oral evidence, there was “no logical reason for rejecting” the nature of the documented threats Polkinghorne had been making that day, which could lead Ms Silva to believe her life and those of her family were in jeopardy.

There was “no rational reason for not accepting the substance of all of this evidence,” Justice Hulme said, adding that it’s impossible not to conclude that Ms Silva perceived that the “the deceased presented a significant danger.”

The conviction overturned

Justice Leeming didn’t agree though. His Honour said it was open for the jury to find Ms Silva’s “final, penetrating stab” wasn’t a reasonable response as she would have perceived it.

However, Justice Lucy McCallum agreed with Justice Hulme, stating that their reasoning largely coincided. And with the two justices making up the majority of the court, the appeal was allowed.

On 7 December 2016, Justice Hulme order that Ms Silva’s manslaughter conviction be overturned, and the sentence imposed by Justice Hoeben quashed. And a judgement and verdict of acquittal were entered.

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