THROUGHOUT the court case there was reference to Triad or Snakehead involvement with the cannabis factory.

Some of the suspects said they were afraid that if they had spoken to police about the murder, their families back in China would be harmed. Both Zhouli Zhang and Bao Lung Huang were said to have had connections with gangsters in China.

The Triad organisations are bywords for Oriental crime gangs and have achieved a mythical status because of their reputation for secrecy and violence.

Triad gangs were originally secret societies formed to protect families in feudal China. The term Triad was given to them by British colonialists, as the symbols used by Triad gangs were based on triangles.

But some gangs, like the 14K group, were formed later.

This particular gang, which was set up as an anti-communist organisation, was mentioned during the murder trial. Based in Hong Kong, it has 20,000 members worldwide, including in Britain, and is said to generate much of its income from drug trafficking. It is also one of the largest and most infamous of Triad gangs.

Detective Superintendent Karnail Dulku said that organised criminal gangs were undoubtedly involved in the Elvington operation.

He said that the cannabis grown there was destined for a Chinese gang based in Aberdeen, but he did not know whether it would have been sold in Scotland or even exported abroad.

Det Supt Dulku also debunked the myth that cannabis gardeners are forced to work under duress. He said that in many cases they actually buy into the operation and are active volunteers.

The fact they are locked into the factory is more of a safety issue, he said. If other criminal gangs found out about the cannabis farm there is a chance they would steal the produce.

By locking workers in with the crop there is less chance of information getting out, he said.