Three men accused of selling cocaine cut with fentanyl in Saskatoon last year are now facing manslaughter charges.

Four people died of overdoses on the weekend of March 10, 2018.

Shervin Beeharry, Japmanjot Grewal and Azam Kabani had been facing a range of drug possession and trafficking charges but, on Thursday, police said those charges will be upgraded to manslaughter, criminal negligence causing death and criminal negligence causing bodily harm.

​In a news release, police said the three men would be in Saskatoon provincial court Friday morning to be formally charged.

Brian Pfefferle is Beehary's lawyer.

"There was early discussions with the prosecution in the days after the original charges were laid. Nothing has been brought to our attention that would suggest anything has changed between those initial discussions and now," he said in an email to CBC.

"As a result, we are very surprised with this development. We anticipate challenging these charges in court."

The overdoses prompted police to issue a public warning that there was a lethal batch of drugs on the street and that it was being sold through a dial-a-dope system.​