Ashley Mervyn Coulston will forever be one of Australia’s most notorious murderers.
He was sentenced to life in prison in 1992 for the brutal slayings of three people in a home in Burwood, Victoria, after he posed as a potential new tenant.
However, police say they believe he may be responsible for a series of rapes in Queensland and New South Wales during the late 1970s and 1980s.
Ashley Mervyn Coulston (pictured) will forever be one of Australia’s most notorious murderers
Detectives claim Coulston flew under the radar for decades before he brutally murdered two student teachers in Burwood on July 26, 1992, after visiting his girlfriend at the hospital.
Anne Smerdon and Kerryn Henstridge were killed after Coulston responded to their newspaper advertisement for a new roommate, according to court documents.
Anne’s brother-in-law, Peter Dempsey, 27, was also at the home when Coulston forced his way in and tied the three of with cream cable ties. He covered their heads before shooting them in an execution-style slaying.
Coulston was arrested five weeks later, on September 1, when he attacked a couple on St Kilda Road, in Melbourne, and threatened them at gunpoint.
The then 36-year-old walked the pair, Richard and Anne Shalagin, into a dark area of the Botanical Gardens before tying up Anne.
Richard promptly attacked Coulston, giving Anne just enough time to run for help.
‘I knew if I didn’t do something then we were dead,’ Mr Shalagin told Sunday Night.
Coulston had seen and responded to an advertisement in a newspaper by Anne Smerdon (right) and Kerryn Henstridge (left) for a new housemate in their Burwood home
Anne soon flagged down two security officers, who called police.
Coulston was arrested and quickly told officers he was trying to rob the Shalagins because he was depressed he was on the dole.
Detectives said they found his claims hard to believe upon discovering his ‘kill kit’, which included a knife, handcuffs, a balaclava, gloves, a sawn-off rifle, bullets and cable ties.
Officers soon began to link similarities between Coulston’s attack on the couple to the Burwood murders.
Anne’s brother-in-law Peter Dempsey (pictured) was also at the home when Coulston forced his way in and tied the three of them down with cream cable ties. He put either a towel or a dressing gown over each of their heads before he shot them each in the head once
Detective Mick Stefanovic said he began looking into the possibility of more crimes committed by Coulston.
It didn’t take him long to find one.
At the age of 14, Coulston abducted two primary school teachers at gunpoint in Tamgambalanga, Victoria, before making the pair drive to Sydney.
However, the two women were able to get help in NSW after alerting a service station employee.
Coulston was sentenced to three months in a juvenile facility.
When he was released, his family moved to Kyogle, in northern New South Wales.
Six years later, a series of rapes were committed on the Gold Coast and in Tweed Heads by a balaclava wearing assailant.
The rapist often attacked couples, binding the male before sexually assaulting the female.
The attacks, which occurred between February 1979 and 1980, ended after the death of Jeffrey Parkinson, who was shot five times after he tried to stop the rapist from attacking his date.
However, police say they believe he may be responsible for a series of rapes in Queensland and New South Wales during the late 1970s and 1980s (Pictured: Coulston outside of court)
In late 1980, Coulston moved to Sydney and began living with Cathy Walker and her husband in Sydney.
Five years later, a serial rapist emerged in the southern Sydney shire, with five attacks in just two years.
Robin Napper, a crime forensics and DNA expert, said Coulston is a suspect in the rapes on the Gold Coast and Sydney, as well as the murder of Mr Parkinson.
Robin Napper (pictured), a crime forensics and DNA expert, said Coulston is a suspect in the rapes on the Gold Coast and Sydney, as well as the murder of Mr Parkinson
Despite Coulston’s DNA being taken in 2000, Mr Napper said it is unlikely it has ever been tested against these crimes.
‘Coulston is a red-hot suspect for the Balaclava rapes in Queensland and, for the Parkinson murder and the Sutherland rapes. When he got caught in Victoria in 1992, you can analyse his timeline, his behavioural instincts – everything about him – and DNA is the final piece of the jigsaw.
‘If you just do that then you can confirm once and for all he is probably one of the most dangerous serial killers Australia has ever had.’