The vandalism and threats began in September against Rita Brown and her Nigerian-born partner Sean Oyinsan in Newmarket. Swastikas and racist epithets were painted and scratched into their car in the driveway and garage door, the Toronto Star reported.
The pair, both 54, moved into the residential neighborhood during the summer and after the first attacks, put the house up for sale, but couldn't get the price they were asking.
After the last attack on Christmas Day, Brown said she was relisting the house for sale.
"We want out as soon as we can get out," she told the Star.
Police Inspector Richard McCabe visited the couple Wednesday to assure them the investigation was in high gear.
"If we catch them, when this goes to court, we're not going to be accepting any plea bargains [or] any reduced sentencing," McCabe said. "Our objective is that they're going to jail."
Mayor Tony Van Bynen said he has lived in Newmarket for three decades and had never seen a similar racist incident.