Reports from South Africa say Sue Howarth was asleep in bed on their farm in Dullstroom, in Mpualanga province, where three men broke in through a window at 2am and tied her and husband Robert Lynn up.
The gang refused to believe the pair did not have a safe and attacked them with a blowtorch, before bundling them into their own pick up truck.
The men put plastic bags over their head and tape around their necks.
They were driven off before Sue was shot twice in the head and Robert in the head, as the couple were dumped and left to die by a nearby roadside.
Robert managed to survive the attack and freed himself to raise the alarm, but Sue died 48 hours later in hospital.
It is believed her life support machine was switched off on Tuesday morning, after doctors said she could not survive her horrific injuries.
MailOnline reported that the incident was the third violent farm attack in the province this month.
Sue, a border collie lover who was originally from Southsea, is believed to have moved to the area about 20 years ago.
A local police spokesman said her husband was treated for multiple stab wounds to his stomach, hands and neck.
He was thrown into bushes with a blindfold over his eyes, and when he found Sue she was near naked and later found to have a plastic bag in her throat.
A passing car saw the couple and stopped to help them.
Her ashes will be flown to Southsea where she will be buried with her parents.