Woman Avoids Prison after Killing Abusive Partner: Fair?

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Jessica Silva had ended her abusive relationship of four years, over which time her partner, James Polkinghorne, had repeatedly tormented her.

She did not report the abuse to police because she was too scared, and she didn’t think police could help her anyway. She claimed to be unaware of how to get an AVO or how they worked.

After the break-up, Polkinghorne spent weeks trying to convince Silva to take him back, becoming increasingly upset by her refusals.

Yet two months after the break-up, Silva agreed to spend the night at Polkinghorne’s apartment together with their two-year-old daughter.

The next day, Silva and her daughter left to visit her parents’ home for Mother’s day.

Polkinghorne was unhappy about this and became increasingly frustrated and angry throughout the day. He called and text messaged Silva during the evening communicating his anger and making various threats, including “I’m gonna cave your f***ing head in”.

Polkinghorne showed up to the parents’ house after 9pm in a drug-fuelled rage. Silva and her brother came out and an argument occurred, during which Polkinghorne punched Silva in the face and ripped her tracksuit pants.

Silva’s brother and father attempted to subdue Polkinghorne, and a struggle occurred between Polkinghorne and the brother. Meanwhile, Silva ran inside and grabbed a knife.

Polkinghorne was on top of Silva’s brother when she came out. Silva approached and stabbed Polkinghorne at least five times on the shoulder, back of his head and back, causing him to die.

Silva was later charged with murder.


Silva admitted stabbing Polkinghorne but argued that it was in self-defence.

Under NSW law, self-defence is a complete defence: which means that a person is ‘not guilty’ if they acted in self-defence.

Under section 18 of the Crimes Act 1900, self-defence is available if someone is:

  • Defending themselves or someone else;
  • Preventing or terminating the unlawful deprivation of their liberty, or the liberty of another person;
  • Protecting property from unlawful taking, destruction, damage or interference; or
  • Preventing criminal trespass to any land or premises, or to remove a person committing such trespasses
  • In order for self-defence to be established:
  • the defendant must believe the conduct is necessary; and
  • the conduct must be a reasonable response to the circumstances as the person sees them.
  • If the defendant raises self-defence, it is up to the prosecution to prove beyond reasonable doubt that self-defence did not occur. If the prosecution cannot do that, the defendant must be found ‘not guilty’.

The verdict in Silva’s case

Silva participated in a police interview after the incident. That interview was played to the jury during the trial. She did not take the witness stand during the trial.

Although the jury rejected Silva’s argument of self-defence, they found her guilty of manslaughter rather than murder because she had acted in “excessive self-defence”.

The maximum penalty for manslaughter is 25 years imprisonment.

Why wasn’t it self-defence?

As stated, the following two conditions would need to be met for self-defence to be established:

  • A belief that the conduct was necessary; and
  • The conduct must be reasonable response to the circumstances as the defendant perceived them.

Although a jury does not give reasons for its verdict, it is likely that the second requirement was not established; in other words, that stabbing Polkinghorne five times in the back, neck and shoulder was not a reasonable response to the threat as Silva perceived it, especially considering that Polkinghorne was not armed.

A finding that the response was disproportionate to the threat can lead to a verdict of manslaughter on grounds of ‘excessive self defence’.

Excessive self-defence:

Excessive self-defence is not a complete defence in the way that self-defence is. It cannot lead to an acquittal, but it does operate to make the offence committed less serious.

Excessive self-defence means that a person is not criminally responsible for murder, but the downgraded charge of manslaughter.

The sentencing

In sentencing Silva, Justice Hoeben accepted that Silva was fearful and highly emotional state when her ex-partner arrived.

He accepted that the stabbing occurred in the agony of the moment and had strong self-defensive elements.

He also found that she was highly remorseful, was of good character, had good prospects of rehabilitation and was unlikely to reoffend.

He ultimately allowed Silva to stay out of prison by imposing a two-year ‘suspended prison sentence’.

Silva and her family were overjoyed with the outcome.

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Ugur Nedim

Ugur Nedim

Ugur Nedim is an Accredited Criminal Law Specialist with 25 years of experience as a Criminal Defence Lawyer. He is the Principal of Sydney Criminal Lawyers®.

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