The Ontario Provincial Police are dusting off their case files to see if any of the eight unidentified bodies found in the crawlspace of his Chicago home are from their country.
It's believed Gacy may have regularly crossed the border during his prime killing years between 1972 and 1978.
He later became known as the "Killer Clown" due to his charitable services at fundraising events, parades and children's parties where he would dress as "Pogo the Clown", a character he devised himself.
OPP detectives will be now look at cases that fit Gacy’s profile, including the type of young men he targeted, from across a wide span of years.
While there are reports at least one Canadian family has contacted American officials to ask about a possible connection to a lost loved one, police have not given any details.
Sgt. Pierre Chamberland told the Toronto Sun they are waiting for U.S. officials — specifically the Cook County Sheriff’s Office that is spearheading the effort to identify the mystery eight — to contact them with more specific information.
He said: “We do have several unresolved cases."