A Calgary man who targeted and sexually assaulted several vulnerable women who worked in Calgary’s sex trade has been sentenced to 12 years in prison.
Mantha, 62, was convicted of six offences in April: sexually assaulting three women — one of whom he drugged, and another he suffocated and assaulted with a weapon — as well as uttering threats against a fourth woman.
On Thursday, Justice Judith Shriar imposed the lengthy prison term following sentencing arguments last month where prosecutor Dominique Mathurin argued for a 10 to 13 year term while defence lawyer Justin Dean asked the judge to consider a five to seven year sentence.
Mantha has just over five-years’ credit for the time he served pending trial, leaving six years, nine months left on his sentence.
Shriar noted that a report prepared by a psychiatrist during the trial found that Mantha has an anti-social personality disorder, a disregard for others and lacks remorse for his actions.
Mantha’s victims were four women who struggled with drug addiction at the time. A publication ban protects the identities of three of the victims. A fourth, Aimee Ert, successfully applied to the court to have the publication ban on her identity lifted.
Ert was in court Thursday as the sentencing decision was delivered.
Mantha was arrested in April 2023 after a massive police search of his rented rural property where he lived in a trailer inside a quonset about 16 kilometres east of Chestermere.
Mantha’s trial started in January 2024 and faced several lengthy delays because he fired two sets of lawyers and then had two health incidents, including a stroke which has left him unable to speak.
During the trial, court heard that Mantha targeted women on the Forest Lawn stroll, a prostitution area in the southeast neighbourhood along 19th Avenue.









