adam lanza dead 1 day before shooting?

[AndreaGail]

saw on another forum, wasnt sure what to make of it. genealogy sites are notorious for having incorrect data but interesting nonetheless

http://www.genealogybank.com/gbnk/ssdi/doc/ssdi/v1:143EB37C71A1FA78

http://i1095.photobucket.com/albums/i462/pofstuff123/oops_zpsa64c2224.jpg

Nancy date of death is the date of the shooting however:
http://www.genealogybank.com/gbnk/ssdi/doc/ssdi/v1:143A177167B62EF8

[Cebu_4_2]

If no one knew who he was and no one had contact how did they know it was him and how did they identify him since he had his brothers ID?