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DNA Expert

DNA evidence can be founded on error or misinterpretation, leading to the courts misunderstanding.rnrnReported DNA results cover merely a portion of the laboratory process and scientific determinations made in a matter.rnrnIndependent forensic DNA expert review determines whether the DNA casefile is affected by error and whether the results genuinely support the allegation, or could instead support a different version of events.rnrnHelen Roebuck is a strongly credentialed and highly regarded forensic DNA expert and DNA expert witness, trusted within both the legal and scientific communities. She is the most prolific and judgment-published independent DNA expert witness in Australia, with her evidence extensively  referenced  across various jurisdiction.rnu003cp data-start=u0022388u0022 data-end=u0022527u0022u003eWe undertake simple and complex matters, acting in u003cstrong data-start=u0022426u0022 data-end=u0022451u0022u003eLegal Aid and privateu003c/strongu003eu003cstrongu003ely funded casesu003c/strongu003e – across u003cstrong data-start=u0022461u0022 data-end=u0022526u0022u003eAustralia, New Zealand u003c/strongu003eand select international jurisdictions.u003c/pu003ernu003cp data-start=u0022299u0022 data-end=u0022481u0022u003eu003c/pu003e

Roebuck Forensics provides robust, independent evaluation of DNA evidence in accordance with current scientific theory and methodology. Expertise includes DNA profiling, biological fluids, STRmix, crime scene examinations, DNA transfer, and bloodstain pattern analysis (BPA). With access to a fully operational forensic laboratory,  laboratory examinations and DNA testing, can also be conducted.rnu003cp data-start=u0022956u0022 data-end=u00221177u0022u003eWith over 25 years’ service to the courts, Ms Roebuck has assessed DNA evidence in thousands of indictable matters, including homicide, sexual assault, drug importation, firearms and explosive device prosecutions.u003c/pu003ernu003cp data-start=u00221179u0022 data-end=u00221291u0022u003eHelen Roebuck’s expert witness opinion is clear, precise and free from unnecessary complexity, explaining challenging scientific issues in plain, courtroom-ready terms.u003c/pu003e

DNA Expert witness

Our full spectrum DNA expert witness forensic consulting service encompasses DNA, bloodstain pattern, biological fluids and STRmix. Drawing upon extensive international and governmental forensic biologist experience at crime scene investigations, laboratory procedures, and highly specialised expert witness evidence presentation before the courts. Roebuck Forensics’ depth of expertise spans the practical, technical, procedural, intellectual and jurisdictional.

With this breadth, we are well placed to assist the courts with serious matters. Incorporating crime scene assessment, sampling, testing, analysis, and review, to form the foundation and contribution towards the preparation and presentation of authoritative DNA expert witness testimony.

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u003cdiv class=u0022rfc-col-6u0022u003ernu003cdiv class=u0022rfc-col-leftu0022u003ernu003ch3u003eCase inquiryu003c/h3u003ernHelen Roebuckrnrnu003ca href=u0022mailto:admin@roebuckforensics.com.auu0022u003ehelen@roebuckforensics.com.auu003c/au003ernrn0493  726 760rnrnu0026nbsp;rnrnu003c/divu003ernu003cdiv class=u0022rfc-col-rightu0022u003ernu003ch4u003eu003c/h4u003ernGPO 390 Sydney NSW 2001rnrn02 8089 0226rnrn9am – 5pm GMT + 11hoursrnrnu003c/divu003ernu003c/divu003e

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Published matters

u003culu003ern tu003cliu003ePublished judgments in which the court has considered and cited Helen Roebuck’s expert opinion.u003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/wa/WADC/2025/69.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eWA v Piccioni [2025] – WA District Courtu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2024/404.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eR v Murphy [2024] – NSW District Courtu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/other/nsw/NSWBCPubInq/2023/4.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eLGBTIQ Hate Crimes Inquiry [2023] – NSWu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eR v Granaghan [2022] – N Ireland Crownu003c/liu003ern tu003cliu003eu003cspan style=u0022font-weight: 400;u0022u003eR v Perre [2021] – SA Supreme Courtu003c/spanu003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2019/349.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eR v Ke [2019] – NSW District Court u003c/spanu003eu003c/au003eu003c/liu003ernu003c/ulu003ernu003culu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2025/47.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eR v Haouchar [2025] – NSW District Courtu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2024/676.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eR v Ahmad [2024] – NSW District Courtu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWCCA/2023/11.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eEvans v R  [2023] – NSW Supreme Courtu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2025/90.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eR v Tsakirios  [2021] – NSW District u003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWDC/2020/707.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eR v Kabbout [2020] – NSW District Courtu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003cspan style=u0022font-weight: 400;u0022u003eR v TAL [2019] – QLD Supreme Court u003c/spanu003eu003c/liu003ern tu003cliu003eu003ca href=u0022https://www.austlii.edu.au/cgi-bin/viewdoc/au/cases/nsw/NSWCorC/2025/93.html?context=1;query=helen%20Roebuck;mask_path=u0022u003eu003cspan style=u0022font-weight: 400;u0022u003eBradley Vincent Balzan Inquiry [2025] – NSWu003c/spanu003eu003c/au003eu003c/liu003ern tu003cliu003eu003c/liu003ernu003c/ulu003e

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‘I engaged Helen Roebuck to independently examine a complicated DNA issue arising from a Rape matter.rnUltimately, the jury returned a verdict of ‘Not Guilty’ on all counts. We couldn’t have done it without Helen.’
Jasmine Pisasale Director, Slade u0026 Parsons
‘a complicated DNA contamination matter. Although the DNA evidence initially seemed damning to the accused, the client was acquitted of all charges. Helen’s advice and evidence at Trial was invaluable.’
Kestin Mildenhall Crockett Chambers
‘At the hearing, Helen’s opinion was preferred to that of the prosecution expert, and proved pivotal to our successful application to have the DNA evidence excluded. The DNA evidence was central to the prosecution’s case, and following its exclusion, the ODPP discontinued all charges against our client. She’s clearly a leader in her field.’
Michael Parella Parella Legal
‘Helen was engaged on short notice. District Court of NSW trial we were faced with a “word on word” situation for a number of alleged sexual assaults, with very little independent evidence to assist the defence. rnThe result was that the DNA evidence was not led, enabling the matter to be much shorter than would have been the case, which proceeded to “not guilty” verdicts on all counts.
John Gooley Stacks Collins Thompson
‘Her professionalism, dedication and expert knowledge were instrumental in the presentation of the defence case’.rn
Gabriel Chipkin Barrister
‘Very professional, organised, and most importantly a very impressive witness. The Magistrate dismissed all charges at the close of the Prosecution case, agreeing that it was dangerous to convict on circumstantial and unreliable evidence.’rn
Jane Murray Solicitor
‘ Helen was also extremely helpful to me in my preparation of examination in chief of her, and of cross-examination of the Crown’s expert. Her evidence in Court was instrumental in establishing the deficiencies in the Crown’s DNA case, and in obtaining a great outcome for our client’.
Simon Kenny Barrister
‘Helen’s comprehensive report resulted in the prosecution determining not to adduce the DNA evidence’.
Andrew Culshaw Barrister
‘Helen’s report was the u0022 final piece of the puzzle u0022 and without it we would not have been able to prove our case’.rn
Michael Lee Lawyer
‘The first person I called was Helen to thank her for preparing me for a successful cross-examination’.rn
Maeve Curry Barrister
‘Opinion was detailed, concise and persuasive. I highly recommend Helen Roebuck’.rn
Amelia Ramsey Lawyer
‘I worked closely with Helen during the lead up to one of South Australia’s longest running murder trials during 2021’.rn
Gilbert Aitken Barrister
‘I’d absolutely recommend seeking her guidance and opinion’
James Leaver Samuel Griffith Chambers
Helen Roebuck CV
DNA Refused Before Trial — Sexual Assault – R v Ke [2019] ⟶

IN judgement

Firearm possession – DNA transfer – Crime scene officer contamination – Investigator mediated transfer
R v Piccioni [2025] – District Court Western Australia

Firearm possession – DNA transfer – Crime scene officer contamination – Investigator mediated transfer

“Ms Roebuck’s opinion more accurately reflects the significance of secondary transfer … I prefer and adopt her formulation.”rn— Judge AstillrnrnThe Court recognised the real risk of investigator-mediated DNA transfer and rules in favour of u003ca href=u0022https://roebuckforensics.com.au/services/dna-evidence-exclusion/u0022u003eDNA evidence exclusionu003c/au003e, ending the prosecutionu003cstrongu003e.u003c/strongu003e

The prosecution’s case in this firearms possession matter relied heavily on DNA recovered from a Smith u0026amp; Wesson revolver. The mixed DNA profile supported the accused as a possible contributor with an extremely strong statistical weighting of 100 billion.rnrnMy independent review of the audiovisual footage revealed extensive forensic handling failures – reuse of gloves between exhibits, movement of items without contamination control, and large portions of the search conducted off-camera. The handling observed created a clear and substantial risk of investigator-mediated contamination – that is, the inadvertent transfer of DNA from non-inculpatory surfaces within the accused’s storage unit, to the firearm through poor evidence-handling procedures by investigators.rnrnAt Voir Dire Judge Astill accepted that, ‘the risk of investigator-mediated contamination is real and necessarily affects the reliability and weight to be attached to the proposed DNA evidence‘ finding that ‘the procedures adopted were not consistent with what was required to avoid investigator-mediated contamination.

DNA contamination challenged – Prosecution Withdrawn – WA v Piccioni
Murder – Bombing – DNA transfer – Crime scene officer contamination – False inclusion
R v Perre [2021] – Supreme Court South Australia

Murder – Bombing – DNA transfer – Crime scene officer contamination – False inclusion

The 1994 fatal bombing of the Adelaide National Crime Association implicating Domenic Perre, is one of Australia’s most sensational and longest running criminal matters.

u003cspan style=u0022font-weight: 400;u0022u003eAfter initially abandoning the prosecution, advancements in DNA science led to further investigation in 2016. u003c/spanu003ernrnu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003e“ I was instructed by defence counsel to review the forensic DNA evidence pertaining to the cloth, which was purportedly associated with the bomb manufacturing process. u003c/spanu003eu003c/iu003ernrnu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003eProsecution intended leading scientific evidence in an effort to prove that Domenic Perre’s DNA was on the cloth.u003c/spanu003eu003c/iu003ernrnu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003eWith a precise interrogation of the DNA profile, I established support for the crime scene officer and Mr Perre’s brother within the profile.u003c/spanu003eu003c/iu003ernrnu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003eI defined the identification of Domenic Perre within the mixed DNA profile as a false inclusion.u003c/spanu003eu003c/iu003ernrnu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003eIn response to my report and opinion, the prosecution proceeded to trial in 2018 in total absence of this expert DNA evidence.”u003c/spanu003eu003c/iu003e

Likelihood Ratios
Firearms – Drugs supply - DNA transfer – Crime scene officer contamination - Not guilty
R v Kabbout [2020] – District Court New South Wales

Firearms – Drugs supply – DNA transfer – Crime scene officer contamination – Not guilty

u003cp data-start=u0022273u0022 data-end=u0022387u0022u003e“I am unable to place any significant weight upon the findings of the accused’s DNA…”u003cbr data-start=u0022362u0022 data-end=u0022365u0022 /u003e— Justice Buscombeu003c/pu003ernu003cp data-start=u0022389u0022 data-end=u0022607u0022u003eCharges alleged that in 2017, the defendant did possess a handgun and a supply quantity of class A drugs, which were seized within a vehicle owned by the defendant, whilst the vehicle was occupied by two other persons.u003c/pu003e

u003cp data-start=u0022633u0022 data-end=u0022788u0022u003e“ I received instructions to review the DNA expert evidence, along with a file that included body worn camera footage of the initial police vehicle search.u003c/pu003ernu003cp data-start=u0022790u0022 data-end=u0022973u0022u003eA review of the footage revealed that the crime scene officer did handle various items within the vehicle relevant to the DNA evidence, without thorough anti-contamination procedures.u003c/pu003ernu003cp data-start=u0022975u0022 data-end=u00221101u0022u003eThe DNA sampling of the gun and drugs revealed mixed DNA profiles, of which the accused DNA contributed to pistol grip sample.u003c/pu003ernu003cp data-start=u00221103u0022 data-end=u00221252u0022u003eFollowing scrutiny of the relevant evidence, I formed the opinion that the DNA evidence did not contribute significantly to the prosecution version.u003c/pu003ernu003cp data-start=u00221254u0022 data-end=u00221325u0022u003eThe DNA expert forensic evidence was significantly ventilated at trial.u003c/pu003ernu003cp data-start=u00221327u0022 data-end=u00221354u0022u003eJudgment- Justice Buscombe;u003c/pu003ernu003cp data-start=u00221327u0022 data-end=u00221354u0022u003e(1) Accused found not guilty in relation to all counts on the indictment.u003c/pu003ernu003cp data-start=u00221327u0022 data-end=u00221354u0022u003eu003c/pu003e

Transfer + contamination
Legal Industry Speaking
SPEAKING

Legal Industry Speaking

Our director and forensic DNA expert Helen Roebuck is a regular contributor to the legal profession, accepting invited speaking roles throughout Australia.rnrnu003cspan style=u0022font-weight: 400;u0022u003eDNA evidence is critically relied upon within the criminal justice system like no other forensic science throughout history.u003c/spanu003ernrnu003cspan style=u0022font-weight: 400;u0022u003eLegal practitioners across the profession, seek knowledge regarding DNA and its contribution to the judicial process, as DNA analysis continues to evolve.u003c/spanu003e

u003cspan style=u0022font-weight: 400;u0022u003e“u003c/spanu003eu003ciu003eu003cspan style=u0022font-weight: 400;u0022u003eThese speaking events serve the legal profession well, whilst also providing me with valuable engagement that offers a greater understanding of the legal communities further needs and expectations of forensic biology and expert evidenceu003c/spanu003eu003c/iu003eu003cspan style=u0022font-weight: 400;u0022u003e” u003c/spanu003e

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legalwise – criminal law conference 2026

  • 13 March 2026

New Zealand defence lawyers association

  • July 2026

NAAJA – CPD

NSW LaW SOCIETY

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Forensic DNA commentary relevant to criminal proceedings

Frequently Asked Questions

What notorious DNA cases has Helen Roebuck worked ?

Helen Roebuck has worked numerous high profile DNA matters since 2001 including; The Family Court Murders, Claremont Serial Murders, NCA Bombing, Lin Family Murders, Madeleine Mccann disappearance, Peter Falconio Murder, The Bicycle Bandit, Scott Austic, Granaghan Bombing, Balzan Police Shooting Inquiry and the LGBTIQ Hate Crimes Inquiry.

How much does a DNA expert cost?

DNA expert Helen Roebuck proffers carefully refined DNA evidence for rates which are comparable to those of a skilled and experienced criminal lawyer.

What is a DNA evidence report?

A DNA expert report authored by Helen Roebuck, will evaluate the crown evidence, biological casefile, relevant documentation and consider the weight of both the prosecution and defence versions. The detailed written expert evidence will follow a clear progression of evidence gathering, evaluation and careful formulation of authoritative opinion.

Does legal Aid funding cover DNA expert evidence?

We are regularly instructed by Legal Aid lawyers and private lawyers with legal aid funding in the service of DNA expert evidence. Our current experience in 2024 is that legal aid funding is not a significant obstacle.

Can we handle matters all over Australia?

Helen Roebuck has extensive and intimate knowledge of the procedures and practices of each and every governmental laboratory throughout Australia. To the extent of familiarity with many of the experts by name and their courtroom manner.rnrnEvidence is regularly provided by Audio Visual Link as well as by way of personal appearance in any state of Australia.

Do we take instruction on DNA matters outside Australia?

Originating from 2001 training at the Forensic Science Service in the UK, Helen Roebuck has been called upon to provide forensic expert opinion in the United Kingdom as well as New Zealand and the United States.

CONTACT
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Acknowledgement of Country

In the spirit of reconcilliation, Roebuck Forensics acknowledges the Traditional Custodians of country throughout Australia and their connections to land, sea, and community. We pay our respect to their Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander peoples today

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LAWYERS – DNA RESOURCE

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