Distinguished officer Mick Horne, 54, died in hospital on Sunday afternoon after he was allegedly attacked by a 20-year-old man in Bega on Friday afternoon following a carjacking.

Murray Deakin allegedly stabbed his grandparents in their Bega home about 3.30pm before hitting the 54-year-old former officer over the head with a hammer about an hour later as he stole his vehicle, police say.

Mr Horne retired as a Senior Constable in 2009 after serving at Bega Traffic & Highway Patrol Command, NSW Police said in a statement on Monday.

"The family would appreciate privacy at this time," a statement read.

Deakin's 71-year-old grandfather managed to escape onto the street outside his East Street home after the alleged attack and flagged down a passing driver for help, however his 69-year-old wife later died at South East Regional Hospital.

The grandfather, who was also injured, was airlifted to Canberra Hospital on Saturday where he remains in a critical condition.

After the alleged attack at the grandparents' home, Deakin escaped in their car and led police on a pursuit before attempting to steal Mr Horne's car and striking him with a hammer, police said.

Mr Horne's wife was unharmed.

The former police officer, who in 2004 was awarded a medal for his 15 years' service to the force, was airlifted to Sydney's St George Hospital where he died on Sunday night.

Deakin, who was apprehended after a manhunt, was charged with the stabbing death of his grandmother and refused bail to appear before Batemans Bay Local Court again on Monday, where he is expected to be charged over the second death.

Australian Associated Press