Three men and a woman have been convicted after one of the most successful covert drug investigations in New Zealand history.
An undercover officer was used in Operation Ghost to infiltrate an organised criminal group. More than 250kg of drugs used to cook methamphetamine was seized in one raid alone.
Police were able to identify Van Thanh Tran as the "boss" who sold pseudoephedrine in bulk to wholesalers with their own supply networks, but kept his "hands clean" by using lieutenants to keep his stockpiles safe and deliver packages on his instructions.
One of those lieutenants was Zigeng Ma, who pleaded pleaded guilty to 12 charges of supplying pseudoephedrine before the trial but denied seven other counts.
A jury at the High Court found Ma guilty of four more offences. He was remanded in custody following the verdict.