A warrant was issued Thursday for Mark Marek on a charge of breaching conditions of his bail, which a judge granted last week.
Police say the 38-year-old was picked up at a gas station after they received a tip that led them to a nearby Edmonton-area storage facility.
Marek was originally charged with one count of corrupting morals for allegedly posting a video from Magnotta while knowing it depicted a real killing.
The video allegedly showed the killing and dismemberment of Chinese university student Jun Lin in Montreal.
Magnotta has pleaded not guilty to murder and is to stand trial in September 2014.
At Marek's bail hearing, the Crown opposed his release, pointing out he had no Edmonton address and had made it clear to police that he planned to go back to his native Slovakia. Police had said he had been living out of his car since he returned to the city.
The defence said Marek had planned to visit family in the eastern European country in September, but didn't intend to run away from his legal problems.
Marek told the judge that officers had already seized his passport.