Canadian Press-A sentencing hearing for a Manitoba man who pleaded guilty to second-degree murder in the killings of his common-law partner and their two young children is set to begin Thursday. Trevis McLeod, 52, admitted in September to the slayings after a forensic assessment found he had not suffered from a mental disorder. Shantelle Murphy, 32; Isabella Murphy, 6; and three-year-old Mason Murphy were found dead in the family’s duplex in Portage la Prairie, west of Winnipeg, on April 10, 2022. Fire crews were initially called to the home after neighbours reported the unit was ablaze. Firefighters would later find the three victims dead in two upstairs bedrooms. Court heard the woman and two children “suffered substantial blunt force trauma to the head and body.” McLeod had a history with…