Laisa Waka Tunidau, 52, had caught the bus home from work and was metres from her house on Cheyenne St, Sockburn, when she was allegedly attacked about 4.20pm on Saturday.
Canterbury District Health Board chief executive Dr Peter Bramley has confirmed the 37-year-old man accused of her murder was a patient of the DHB's specialist mental health service at Hillmorton Hospital who had been on community leave.
Other media have reported several staff members have resigned from the hospital since the incident.
"We are working with all affected staff and have support in place," she said.
A full review has been launched by DHB bosses following the incident.
The CDHB announced it is carrying out a review after days of questions into how the 37-year-old man was allowed into the community.
Tunidau's s 11-year-old son has reportedly been left "traumatised" after watching emergency services try to save a woman outside his family home, and not then knowing it was his mother.
A judge ordered reports to assess the man's mental health.
But there are unanswered questions around how the man was released from the mental health unit.
Christchurch-based National MP Gerry Brownlee said the review needs to make it clear where the failings were.
Brownlee said someone made the decision to let the man out despite his dangerous circumstances.
-By Devon Bolger