A carjacking victim, who police say was struck in the head with a hammer by a man who just stabbed his grandmother to death on the NSW south coast, has died.
The alleged attacker, Murray Deakin, who is behind bars, now faces a second murder charge.
Deakin, 20, allegedly stabbed his grandparents in their Bega home on Friday afternoon.
His 71-year-old grandfather managed to escape onto the street outside his East Street home after the attack and flagged down a passing driver for help, however his 69-year-old wife later died at South East Regional Hospital.
The grandfather was fighting for his life on Saturday after being airlifted to Canberra Hospital.
After the attack Deakin escaped in his grandparent's car and later struck a 55-year-old male driver over the head with a hammer as he stole his vehicle, police say.
That victim was airlifted to Sydney's St George Hospital where he died on Sunday evening.
Deakin faced Batemans Bay Local Court on Sunday where he didn't apply for bail and it was formally refused.
He is currently charged with one count of murder and two counts of wounding with intent to murder.
One of the wounding charges is expected to be upgraded when he faces the same court again on Monday.