RCMP say they have arrested Shane Gregory Babitsch, 21, of Grande Prairie.
He is to appear in provincial court Wednesday.
Courtney Breanna Johnstone, 26, of Grande Prairie was reported missing on Jan. 30.
RCMP say she is dead, but officers have not found her remains.
Police say the fact that Johnstone's family and friends were very quick to report her missing helped their investigation.
"Courtney's family and friends were fast in reporting Courtney missing," Superintendent Ray Noble said Tuesday.
"This, coupled with a concentrated effort by all of our investigators, led to the arrest of the person we believe responsible for her death. We offer our sincere condolences to Courtney's family."
RCMP were searching the Aquatera Waste Management site in Grande Prairie for Johnstone's remains.
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