AN investigation that began in 2015 has seen its final charges laid following the release of a 34-year-old from a NSW prison.

Operation Armscote was a complex investigation into a highly sophisticated cannabis grow house syndicate operating within the ACT. The investigation seized about 1220 cannabis plants from 14 search warrants.

Seven people were charged with cultivating a controlled plant and other criminal group offences. Those matters have all been finalised.

One arrest warrant remained in place for a 34-year-old Vietnamese national who investigators linked to the criminal syndicate.

On May 9 police extradited the man from NSW following his release from prison.

He is charged with three counts of cultivating a trafficable quantity of cannabis and three counts of cultivating a commercial quantity of cannabis.