Tauarea was still alive when he was rushed to hospital, but succumbed to his injuries while being treated under emergency at Rarotonga Hospital, local authorities said.
It has since been revealed Rimamotu - who was among prisoners doing community work when he made his escape yesterday - had slipped away to a spot nearby, where he had stashed lethal supplies in what is understood to be a shipping container.
"Rimamotu was allowed to access a container near his home while engaged with a prison work gang detail," Cook Islands Acting Minister of Police, Nandi Glassie, said.
"It is believed that the firearm and ammunition was extracted from this container.''
The incident is thought to be the first multiple fatal shooting in the island nation's history.
Members of the Cook Islands community - both in the islands and overseas - continue to share their shock and grief about the incident.
Many have paid tribute to the victims, as well as Dean's young son; who has now lost both his mother and father in tragic circumstances.
Glassie praised the work of local police, including the Police Commissioner, officers and prison wardens involved in the operation.
"I am pleased that all our local authorities conducted themselves with a high degree of professionalism and integrity to uphold the safety and security of the public at all times while in a high-risk situation,'' he said.
Glassie also acknowledged how the wider Cook Islands community was feeling, following the tragedy.
"This has been a terrible ordeal and we can take some comfort in that it has been resolved and concluded relatively swiftly.
"While I do want to express our collective sadness over the deaths of these individuals - Mary Dean, 47, Roger Tauarea, 45, and Christopher Rimamotu, 41 - and say how deeply this has affected our community and island, we must now look forward with resolve and strength so that the tragic events do not impact upon the lives of innocent people and the families involved in ways that will have serious and damaging effects."
