NEW : The couple , who disappeared with their small sons , were killed , authorities say . NEW : Remains were identified through dental records . Comment: Joseph and Summer McStay and their sons vanished in 2010 .
NEW : The couple , who disappeared with their small sons , were killed , authorities say . NEW : Remains were identified through dental records . Two other sets of remains also found might be couple 's sons , authorities say . Joseph and Summer McStay and their sons vanished in 2010 .