A Countdown staff member and mother of four remains in hospital after the stabbing rampage at the central Dunedin Countdown.
Her son, who asked not to be named, said doctors appeared confident she would recover from her injuries.
He spent all of yesterday by her bedside and described the knife wounds as "pretty bad".
The man told the ODT he understood his mother had been blind-sided during the incident, but had been unable to confirm the exact sequence of events.
"She wasn't really talking much yesterday," he said.
Yesterday's news had been so devastating, the victim's son said he could not even remember how he had found out.
He said he was struggling to take it all in and his siblings felt the same.
Corrections Southern regional commissioner Ben Clark said their focus was ensuring that the staff member, their family and colleagues had all the support they need during this ''stressful and difficult time''.
''We would like to thank the emergency services, police and supermarket staff for the help they provided following the incident.
''To respect the privacy of our staff member and their family, we will not be providing any further comment.''
A corrections officer was also identified as one of the four injured in yesterday's violent knife attack.
The man and his wife were inside the Cumberland St store in central Dunedin when a man with a knife allegedly attacked four people, including two supermarket workers.
Corrections southern regional commissioner Ben Clark this morning confirmed one of those injured was an employee.
Clark said the service was focused on ensuring the staff member, their family and colleagues had all the support they required during a stressful and difficult time.
"We would like to thank the emergency services, police and supermarket staff for the help they provided following the incident.
"To respect the privacy of our staff member and their family, we will not be providing any further comment."
It is believed the Corrections officer worked at the Otago Corrections Facility and his wife, who was alongside him in the store, was a nurse.
One of the employees injured in the attack was believed to be the store's manager.
Anne Coulthard told the Herald he was a long-time friend and worked alongside him at the beginning of his career in the late 1990s.
"I have seen and watched him grow from a young teenager to a wonderful store manager. And always looked forward to seeing him when I shopped there, we often laughed about days past when he was so much younger."
Coulthard, a former supermarket worker herself, said it was a sad day when such a tragic event happened in Dunedin.
The injured manager had previously worked at Countdown Andersons Bay in South Dunedin.
This morning police said four people remained in hospital. Three of the injured were in a serious but stable condition. A fourth person was in a moderate condition.
Countdown head of corporate affairs Kiri Hannifin told the AM Show said the two staff members injured in the attack were doing better today.
"We were very worried about them overnight but they are doing okay," she said.
Police said a 42-year-old man had been charged with four counts of attempted murder.
He is due to appear in the Dunedin District Court today.