He had moved to Australia about 10 years ago and was "just your regular, down to earth bloke" who loved his family and worked hard, the family member said.
Mr Hargreaves lived with one of his daughters and son-in-law in Sydney, she said.
The death had devastated the family and they hoped police would quickly catch the alleged offender.
"This is really quite hard for the family. He moved over there, then his daughter moved over there to be with him, and he had a brother over there too," she said.
"You could understand if he died of natural causes or he died in a car accident, but for somebody to go out and deliberately do that, it's hard."
Meanwhile, in Sydney, Carol Cramp, the mother of Gordon Cramp, has made a plea for her wanted son to give himself up to police.
"I need you to hand yourself in," Ms Cramp said during a press conference, while flanked by senior officers at New South Wales police headquarters in Parramatta yesterday.
"Me and your brother will stand by you and your family. Please, just hand yourself in," she urged.
Sydney police said Mr Cramp was dangerous, had access to a firearm, and they advised members of the public not to approach him.
Detective Inspector Michael Willing said it was not known whether Mr Cramp was still in Sydney or had managed to flee the state.
"We have information that is coming in but we are keeping our options open and he could be anywhere," Mr Willing said.
"Hopefully somebody out there knows where he is and will contact us."
