A woman was convicted Friday of stabbing her mother to death over four years ago at the Burlington County apartment they shared, authorities said. Marisa Rivera, 27, of Mount Laurel, was found guilty of murder and weapons-related offenses, according to a statement from the Burlington County Prosecutor’s Office. The body of Rivera’s mother, 56-year-old Denise DeNapoli, was discovered in their home at the Ramblewood Village Apartments the morning of Sept. 6, 2019, by officers from the Mount Laurel Police Department, the office said. Police had gone there to conduct a wellness check after co-work…