Interpol joined the search for 29-year-old Luka Rocco Magnotta at the request of Montreal police, who suspect he fled the country, the Canadian Broadcasting Corp. said.
The investigations began Tuesday when two parcels sent through the mail to Ottawa addresses were found to contain a hand and left foot. The same day, a headless and limbless torso was found in a suitcase on a Montreal curb.
The identity of the victim hasn't been released, but police said he was in his 30s and knew the suspect. Police said the missing body parts hadn't been found.
Police said Magnotta, who also goes by the aliases of Eric Clinton Newman and Vladimir Romanov, used the Internet extensively and once posted a video of him torturing and killing kittens, The (Montreal) Gazette said.
He also claimed in postings to be a former stripper and pornography actor.
Montreal police Cmdr. Ian Lafreniere told the CBC Interpol was summoned because of Internet evidence.
"He left a letter on a Web site mentioning how to disappear for good," he said. "This is a very, very ... deranged person, so a lot of people have called and we got details now."