SWAMPSCOTT – Investigators are still sifting through ashes to find the cause of the Thursday afternoon blaze at 77 Plymouth Ave. that killed Philip Kenneally, 61.According to Chief Richard Carmody, the department received a call for heavy smoke at that address at approximately 1 p.m. Thursday.He said when rescue personnel arrived on the scene the fire had already made a lot of headway and the two-story home was filled with heavy black smoke.Firefighters located Kenneally in the basement of his home, which contains a small workshop.Detective Ted Delano, who is working on the investigation with Fire Investigator Robert Faulkner and state fire marshals, said he is unsure when the investigation will be complete.