The oldest inmate on death row in the United States has died of natural causes.

Viva Leroy Nash, 94, was sentenced to death by an Arizona court in 1983 for escaping from jail and murdering a salesman.

His lawyer, Thomas Phalen, explains how Nash was able to avoid the gas chamber and then lethal injection.

"He had had several major heart attacks and his dementia got so acute that even the Department of Corrections personnel removed him from death row towards the end and put him in a medical facility at the prison," Mr Phalen said.

"It's a celebratory time because the man is dead, everyone can be at peace and we didn't have to go through the horror of an execution."

- BBC