NEW : The couple , who disappeared with their small children , 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 . Surveillance video taken that night shows a family fitting the description of the McStays walking into Mexico . Joseph and Mary McStay and their sons disappeared in 2010 .
NEW : The couple , who disappeared with their small children , 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 Mary McStay and their sons disappeared in 2010 .