The teenage grandson of a South Penrith woman found dead with multiple stab wounds has been arrested over her death.
The man, 19, was arrested by Victoria Police at a home at Nhill, in western Victoria 375 kilometres from Melbourne, on Thursday morning.
It followed the discovery of the body of the 67-year-old woman inside her Chesterfield Road home on Wednesday morning after friends raised concerns for her welfare when she failed to turn up to her regular bingo game at Penrith RSL Club.
The woman was last seen by neighbours on Friday and detectives are investigating whether the brutal attack occurred sometime over the weekend.
She suffered multiple stab wounds in the attack.
The breakthrough came after Strike Force Tillock was established by local detectives and the homicide squad to hunt down her alleged killer.
Police arrested the man at a rural Victorian home about 9.15am. He was expected to be taken to Melbourne where he will be charged with a NSW warrant for murder.
He is expected to appear at Melbourne Magistrate's Court on Friday where Strike Force Tillock detectives will apply for the man's extradition to Sydney.
Neighbour Barbara Dorbon told Seven News "nothing like this [had] ever happened" on their quiet street.
"She didn't turn up at bingo so they knew something was up. But I suppose nobody went down, sort of, to knock on the door," she said.
Police found the woman's red 2009 Subaru Impreza, registration BHX 20A, at a Penrith car park on Wednesday afternoon, a police spokesman said.