WA coroner probes one-punch inmate attack

Inmate Troy Allan Roginson was killed in a one-punch attack after a dispute about a table in the dining area of a Perth prison more than two years ago.

Robert Thomas Garlett, 20, pleaded guilty to assault occasioning the death of the 35-year-old at the Wooroloo Prison Farm in April 2014.

He was jailed last year for two years and eight months on top of the sentence he was already serving.

Coroner Sarah Linton is now investigating the circumstances surrounding Roginson's death and in her findings will comment on the quality of his supervision, treatment and care in custody.

In his opening address on Monday, counsel assisting the coroner Lyle Housiaux said at the time of his death Roginson was serving a prison sentence for dishonesty and drug offences.

Roginson had approached Garlett in the meals area and told him he had taken his table, before sitting somewhere else.

Garlett later confronted him near some rubbish bins and punched Roginson in the chin, causing the victim to hit his head on concrete.

"Mr Garlett did not provide any care to the deceased and he ran away," Mr Housiaux said.

"A third prisoner, who had witnessed the entire incident, alerted prison staff and medical care followed."

Roginson was initially transported to Swan District Hospital then transferred to Royal Perth Hospital later that evening.

His condition was noted as critical and he was placed on life support, but died from a catastrophic brain injury, Mr Housiaux said.