Case study in Forensics - Ashley Coulston

Ashely Mervyn Coulston is known as the ‘Burwood triple murderer’ he murdered three innocent victims in cold blood on 29 July 19921. Coulston had gone to a Burwood house under the guise of renting a room in the house that had been ‘advertised in the Herald Sun’2. Coulston had a bag that contained a . 22 rifle, ammunition, a homemade silencer and plastic cable ties. Coulston bound, gagged and covered the victim’s heads (using a towel or dressing gown) and shot each in the back of the head at point blank range3. I will briefly outline the circumstances of the case and how the perpetrator – Coulston, was eventually captured and the evidence that flowed to convict him for the triple murders in Summit Road, Burwood. In this case study I will examine the forensic evidence (limited to the main ballistic evidence), that was presented in the criminal trials and the forensic evidence that was introduced by the prosecution. Background Coulston was caught by police not for the murders in Burwood but for an armed robbery that occurred several months after the murders in July. Coulston had approached a couple who were returning to their car parked near the National Gallery in St Kilda Road. Coulston was wearing a balaclava and carrying a . 22 calibre rifle when he approached the couple in their car4. The couple believed the assailant was after money; so they threw some money at Coulston hoping that he would leave5. Coulston grabbed the money and forced the couple from the car. He then forced the female to the ground and tied her hands with the cable ties. At that moment the male partner of the couple noticed that Coulston had placed the gun on the ground and he took the opportunity to grapple with Coulston, thus allowing the female to run. The male also fled, with both calling out for help. Two security officers near the scene heard screams for assistance, and subsequently called for police. Coulston followed the couple and fired shots at the security officers which hit one of the officer’s in the hip6. When police arrested Coulston they found a sawn off rifle, a homemade silencer that was made from a motor vehicle oil filter, a knife and plastic cable ties7. Forensic evidence The police forensics department found that the bullets recovered from the scene of the Burwood triple murders had come from the same gun used in the St Kilda armed robbery8. The police also found that the cream cable ties used on the female victim in the armed hold-up were the same brand as those used in in the Burwood murders9. Forensic evidence also established that blood splatter from a dressing gown found over the head of one of the Burwood victims was the same blood that had splattered onto the oil filter of the rifle, used as a silencer10. Police were also able to use the fingerprint of Coulston found on his Melways Street directory that marked the page of the Summit Road, Burwood triple murders11. These pieces of evidence were used to place Coulston as the prime suspect in relation to the three murders in Burwood12. In relation to the specific ballistic evidence; there was considerable debate over the possible contamination of the evidence by Senior Constable Ray Vincent – police forensic examiner. Mr Vincent appears to have incorrectly labelled a job card used to record the test firing of the rifle. The Court of Appeal was less than impressed with the defence’s proposition that due to the error there was a possibility that the bullets had been substituted to make it look like they had been fired from the . 22 Sterling rifle13. Both the High Court and the Court of Appeal dismissed the notion of the evidence being tampered with14. The prime evidence that was used to convict Coulston was the . 22 Sterling rifle he had in his possession, when he was arrested in relation to armed robbery and attempted murder of the security officers in St Kilda Road, Melbourne15. Specific Forensic Evidence There were several specific pieces of evidence that were found at the Burwood murder scene:16 1. There was no sign of forced entry; 2. That the flat was neat and tidy – not disturbed; 3. That the 3 victims had their hands bound with cream coloured tie straps and socks placed in their mouths; and, 4. One of the victims had a dressing gown placed over her head whilst the others had towels. 17 5. A Sterling . 22 rifle was one of a list of weapons that had similar rifling marks to two of the bullets used in the murders – one of the bullets was indistinguishable18. The Sterling rifle that Coulston used in the armed robbery was suspected to have been the weapon used in the Burwood murders19. The police forensic expert Senior Constable Ray Vincent was able to match the distinct impressions left on the bullet by the particular firearm, ‘much like a fingerprint’20. The firearm barrel is manufactured by using a type of drill (reamer) to cut the barrel so it has ‘spiral grooves cut into the inner surface of the barrel’21. The spiralling enables the bullet to spin and therefore maintain a more accurate trajectory22. When the ballistics expert inspects the bullet, he measures the spaces between the markings on the bullet called grooves and lands, and in particular if they twist either to the right or left23. Mr Vincent was able to count the number of grooves, their width and depth, together with the angle of the twist, and compiled a list of manufacturers that had similar rifling marks – one of those was a Sterling . 22 rifle24. Coulston’s defence tried to discredit the ballistic evidence given by Mr Vincent25. By indicating that: 1. 250 bullets had been test fired from the rifle to make a comparison; 2. the job card used to record the firings was incorrectly dated – it was dated August 1993 instead of August 1992; and, 3. the bullets used had been substituted at a later stage. In relation to point 1, His Honour Chief Justice Brenan responded by suggesting that ‘the rifling on these bullets fired at a stage before the burring on the front of the barrel might have changed the perspective of them’26. In essence His Honour was making the comment that the defence may be suggesting that after multiple firings of a weapon the profiling on the bullet may change indicting a possible error being made in the make of the firearm27. In relation to point 2, the defence proposed that the evidence may have been tainted by the fact that ‘something was wrong in the handwritten†¦Ã¢â‚¬ ¦addition to the document†¦Ã¢â‚¬ ¦which was a list of weapons having the same rifling characteristics as the weapon inferentially used in the murders’28. The defence was trying to put doubt in the jury’s mind by stating that the list of weapons noted by Vincent, that had the same markings as the murder weapon, was made after Coulston was arrested for the armed robbery in September 1992, noting that Coulston had one of the weapons on the list29. In relation to point 3, the defence stated that the rifling, that is the ‘characteristics of the weapon’ †¦Ã¢â‚¬â„¢used in the murders, was based on Vincent’s forensic examination of the bullets’. The bullets had †¦. ‘six lands and grooves with a right hand twist with the lands wider than the groove, land . 063 and groove . 048, Vincent prepared a list of rifles which possessed those characteristics. ’ ‘The list of rifles with those characteristics would therefore identify the murder weapon’30. The defence utilised the services of an expert witness; Mr Barnes (a former Forensic officer later to be discredited) who indicated he was ‘not able to see how you could prepare a list of [weapons] based on those characteristics’ (the land and groove markings on the bullet) to the list of weapons prepared by Mr Vincent31. The inference drawn was the bullets used by Mr Vincent may have been substituted at a later stage. Both the High Court and the Court of Appeal both regarded ‘the issue as improbable’ and regarded ‘Mr Vincent as a credible witness’32. Blood splatter and gun residue Due to the word limit I will only touch on the issue of the other evidence that was gathered from the crime scene in Burwood, as it was not as significant as the ballistic evidence. A forensic scientist had determined that the blood stains from the dressing gown matched blood found on the oil filter that was used as a silencer33. Another forensic scientist determined that the lack of gun residue on the dressing gown was consistent with someone being shot a close range34. These pieces of evidence led to the police interrogation of Coulston who answered â€Å"no comment’. Coulston remained silent in regards to the murder charges throughout the trial and has maintained his innocence to the charges of murder35. Coulston ultimately appealed his conviction of murder to the High Court who dismissed his appeal on the ground that it had ‘no prospects of success. 36 He is now serving three consecutive life sentences and is never to be released. Conclusion The attention to detail and the corroboration of the evidence by another Forensic Officer is tantamount to the credibility of the evidence put before the court. Any mistake made by the Forensic officer can jeopardise the trial and possibly allow a murderer to walk free, as a jury is required to make a decision on the basis of beyond reasonable doubt. In this case, if there was doubt around the date of the job card, the list of weapons and the bullets used; this may put enough doubt in a juries mind to find Coulston not guilty37.