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.
Other alleged Tran helpers on trial were his relative Xijin Xu and Jiu Mei Zheng, who ran the mah jong den he frequented.
Around 5.5kg of pseudoephedrine was found in a suitcase at Zheng's premises but her lawyer, Gary Gotlieb, said she had no knowledge of what was inside.
She was convicted by the jury of five charges of supplying pseudoephedrine and one of possession for supply, while Mr Xu was found not guilty of two charges of supplying a Class-B drug and was discharged.
Two others on trial - Zhi Tong Li and Hau Phan Lam - were alleged to be wholesale customers of Tran.
Also known as Alex, Li was convicted of 16 pseudoephedrine charges and two methamphetamine charges in relation to 500g of P.
Lam was convicted of one pseudoephedrine charge, but discharged on the other. Both were remanded in custody.
Sentencing will take place in the High Court at the end of June.