A man accused of three cold-case murders targeted vulnerable people and killed each of them violently while searching for valuables to fund his drug habit, a judge has heard.
Steven Leslie Hainsworth, 49, faced the South Australian Supreme Court on Tuesday to stand trial for the murders of Phyllis Harrison, 71, at Elizabeth South in 1998, Beverley Hanley, 64, at Elizabeth North in 2010 and Stephen Newton, 55, at Mt Gambier in 2011.
Hainsworth, 49, of Mildura, has pleaded not guilty to the three murders.
He is facing a judge-alone trial before Justice Adam Kimber and it is expected to go for up to three months.
Prosecutor Amelia Cairney said each victim was killed in their home, they were known to the accused, lived near him, all three had their homes ransacked and Hainsworth's DNA profile was found at each crime scene.
"Mrs Harrison was stabbed to death with a knife, Ms Hanley suffered blunt and sharp force trauma from more than one object and Mr Newton was punched to death," Ms Cairney said.
"The mode of death may be different and the murders may span a 13-year period, but on the prosecution case, it is no coincidence that each victim was known to the accused and lived nearby at the time of their death.
"It is no coincidence that each victim lived alone and in their own way presented with vulnerability.
"Nor is it any coincidence that each crime scene showed evidence of property being searched or items missing, because on the prosecution case, the accused entered each house looking for money or items of some value."
Mrs Harrison's body was found on the floor of the kitchen of her Elizabeth South home by her daughter and grandson on March 3, 1998.
Ms Cairney said Hainsworth, then aged 23, was living next door, moving in weeks before the murder.
He had entered via an unlocked door at the rear of the house about 8pm on March 2, 1998 looking for items of value, she said.
"Having encountered Mrs Harrison in her kitchen, he stabbed and killed her," she said.
She said Hainsworth's DNA profile was found on Mrs Harrison's body, her clothing and on carpet near her body.
"Your honour will hear evidence of admissions made by the accused to various people in the aftermath of the murder, including to using a knife to having stabbed Mrs Harrison."
In 2007, a knife was found in a hedge two doors down from Mrs Harrison's house.
Ms Cairney said in Ms Hanley's alleged murder, the court would hear she was a paternal aunt of the accused and they lived within walking distance of each other.
Her body was found by her sister at her home on October 6, 2010.
"Your honour will hear that Beverley Hanley suffered blunt force trauma to her head along with incisions to the left and right side of her head," she said.
A cricket bat covered in blood was found near her body and bloodied footprints were observed throughout the house.
Ms Cairney said the charge relating to the death of Mr Newton would rely on circumstantial evidence, including DNA evidence and evidence about items missing from his home, which were later recovered by police.
It would also rely on an eyewitness account from Sarah Evans, who was Hainsworth's partner at the time.
Mr Newton was last seen on September 24, 2011 and his badly decomposed body was found in his home by police on November 4, 2011, covered in rubbish and debris.
"Mr Newton was killed by a number of heavy punches inflicted by the accused, who then went on to search his house and steal his property," Ms Cairney said.
Hainsworth's counsel, Andrew Fowler-Walker, did not make an opening statement.
The trial continues.
