VANCOUVER — A British Columbia government lawsuit seeks to merge almost a decade of litigation into a single, high-stakes test of whether the province can finally seize a fortified mansion near the U.S. border that was first swept up in a 2014 fentanyl investigation, raided in 2016, and is now at the center of a new synthetic-opioid case alleging its occupants contracted with the leader of Mexico’s Sinaloa Cartel to flood narcotics into Canada.
