An underground cannabis factory containing £350,000 worth of the drugs is the first of its kind uncovered in Northern Ireland, the High Court heard today.
Police found three purpose-built rooms full of 600 plants following a surveillance operation in Co Down.
Covert video footage, photographs and audio recordings formed part of the investigation which resulted in five men being charged, prosecutors revealed.
Details emerged as one of the accused was refused bail.
Brendan Rice (48) of Dundrum Road, Newcastle, faces charges of cultivating and possessing cannabis with intent to supply.
He was arrested along with the other suspects when police raided premises on the Derryneill Road, Castlewellan on May 21.
Keys found on him were said to be for the shutter on a shed complex which housed the cannabis growing operation.
Kate McKay, prosecuting, said searches revealed plants with a potential £350,000 street value at three different growth stages.
She told the court: "Concealing them underground in a purpose-built area, on top of which a large shed was built, had never before been encountered in Northern Ireland."
The concrete chambers were accessed through a vehicle examination pit, Mrs McKay disclosed.
Walls were lined with lighting, hose-piping and other equipment to aid the cultivation process.
Cars worth around £100,000 were also seized in the police swoop.
Confirming that surveillance was used in the investigation, the barrister added: "Police are in possession of a number of covert audio and video recordings in respect of this applicant."
She claimed Rice played a greater role in the alleged illegal operation than merely growing the plants.
"Clearly this is an organised crime gang and police believe it did take a considerable degree of planning to get this concealed cannabis factory set up," Ms McKay contended.
Defence counsel argued, however, that Rice's lifestyle was not one of any wealth.
He cited a potential medical condition which could require urgent intervention and said the accused's family can put up £5,000 in cash to ease any concerns he may not turn up for trial.
But refusing bail, Mr Justice Treacy ruled there was a risk of re-offending.
The judge added: "The investigation is at an early stage and it appears there are other matters being investigated by the police."