Dutch police say it's likely the members of rival drug gangs would be kidnapped and held in these rooms.
The plan involved multiple teams of people, fake police uniforms, traffic stops and bulletproof vests – a plan uncovered when police cracked an encrypted messaging system.
Those arrested claimed they never planned to actually torture people and the cells were built purely as a way to frighten their rivals.
The sentences range in severity from one to nine years and an eleventh person was acquitted.
It's not Haanstra's first experience with the law. In 1999 he was accused of killing drug dealer Terri King execution-style in the Tararua Ranges.
King had been importing drugs from South Africa – and the Crown alleged Haanstra owed him $8000.
The Crown claims Haanstra lead King into the ranges with a lure of a buried cache of MDMA, then shot him in the back of the head with a rifle.
A hunter discovered King's body two months later.
Haanstra was the last known contact of King, but the then 22-year-old denied any involvement in the death.
His defence said King's death was likely due to relationships souring between King and the South African men he was importing drugs from.
After a two-month, high-profile trial, Haanstra was acquitted. King's murderer was never found.
