Officers have charged a Stony prison employee and a number of others believed to have helped supply inmates with illegal drugs.
Ephedrine pills, morphine tablets, cannabis oil and cash were seized during the investigation.
RCMP said Christopher Sposito, 29, of Selkirk faces charges for possession of a controlled substance for the purpose of trafficking and possessing proceeds of crime.
At the time of his arrest, Sposito was a casual employee at Stony Mountain Institution but was not a guard, said RCMP.
Officers announced multiple other arrests in the case.
Ashleigh Sullivan, 24, of Winnipeg faces a charge for possession of a controlled substance for the purpose of trafficking and conspiracy to traffic a controlled substance, said RCMP.
Police added that Sullivan is believed to have a relationship with an inmate at the facility.
Both Sullivan and Sposito have been released from custody and have court dates set for Oct. 17 in Winnipeg.
Two Stony Mountain inmates face charges as part of the investigation.
Stephan Konowalchuk, 30, and Joel Bruneau, 23, each face two counts of conspiracy to traffic a controlled substance, said RCMP.
RCMP said Stony Mountain Institution has a confidential tip line for reporting drug trafficking at 204-344-6000.
