SALEM – The double murder trial was to begin today for a Lynn man who allegedly slit the throats of his grandmother and mother before fleeing for Canada in May 2012.Joseph Wright III, 25, has been charged with murder in the deaths of Donna Breau, 54, and Melba Trahant, 83, in May 2012. Breau was Wright’s mother, and Trahant his grandmother.Police found the women’s bodies underneath blue plastic tarps behind the Lynnhurst School in Saugus early May 1, 2012. Each of the women’s necks had been cut “from ear to ear,” according to a prosecutor.Police identified Breau through her fingerprints and then went to her Sheridan Street home. Officers reported finding a blood-covered couch in Trahant’s first-floor apartment and a “bed saturated and soaked with massive amounts of blood” in Breau’s second-floor bedroom. Police said “blood drag” marks led down a stairwell to the residence’s driveway, and officers recovered a knife at the house.Investigators focused on Wright after learning Trahant’s car was missing and family members could not find Wright.Wright was arrested just after crossing into Canada while driving Trahant’s Toyota Corolla. Wright allegedly led border agents on a car and foot chase and, when caught, confessed to slitting the victims’ throats and dumping them in the schoolyard.Wright has pleaded not guilty to two counts of first-degree murder in connection with the crime.He has been held without bail since his May 3, 2012 arraignment in Lynn District Court. A grand jury indicted Wright in June of that year, and he pleaded not guilty to the two counts of murder at his Aug. 10, 2012 arraignment in Salem Superior Court.Wright’s attorney declined to comment on the case.Jury selection is scheduled to begin today in Salem Superior Court.