"I shot him," a prison officer known only as Officer A told triple-zero operators moments after he gunned down inmate Dwayne Johnstone in northern NSW.
The triple-zero phone call was played during a NSW Supreme Court murder trial on Thursday and was made by the officer, whose identity has been suppressed, on March 15, 2019.
"An inmate has tried to escape and I've shot him," he said.
He told the operator, referred to as Emma, that an ambulance was treating Johnstone on site at Lismore Base Hospital.
"And he was trying to escape, that's right?" Emma asked.
"Yes, yes, yes," the officer replied.
Officer A has pleaded not guilty to murdering the then 43-year old inmate when he took off around 7.30pm on March 15.
Previously in the trial, the jury heard that four shots were fired at Johnstone. After the first two missed, the third and fourth rounds felled the inmate.
Nurse Renee Dunstan was working at Lismore Base Hospital that night when she heard the gun shots. Taking cover under her desk, she also called triple zero before being asked to run out and help resuscitate Johnstone.
The trial continues.