Five people have been charged in what police say was a conspiracy to smuggle drugs into the Edmonton Remand Centre.
Police launched an investigation in July after staff intercepted a letter addressed to an inmate which contained small amounts of methamphetamine and prescription drugs.
Police believe the drugs were intended for sale to other inmates and that can be very lucrative due to higher prices they can charge within the facility's walls.
"It's about ten times the price of street value," said Insp. Greg Preston from Edmonton Police.
"There's quite a premium on being able to get a drug into the institution. We have controls in place to try and limit the amount that gets in. But obviously there are ways that people can get them in and they do succeed on occasion."
The letter containing the drugs falsely appeared to come from the inmate's lawyer, Preston said.
No lawyer was involved in the conspiracy. Police believe the people involved were trying to take advantage of the protected communication allowed between solicitor and client.
All five face charges of conspiracy to traffic in a controlled substance. Three of the accused were in custody at the time charges were laid.