They were poisoned by carbon monoxide fumes and their deaths made to appear as suicide.

Zola died of asphyxiation, poisoned by carbon monoxide from a blocked chimney, when he was 62.

The police say charges could potentially be laid after a West Auckland family was poisoned by carbon monoxide in their home.

Autopsies on the passengers found that they had been poisoned by carbon monoxide emissions, but no reason for the poisoning was ever found.