now, adam gibson did. >> reporter: rigor mortis?reporter: the mechanics of rigor mortis go like this. upon death, a human's muscles start to stiffen. but to the detective, it looked as though cory's arms and hands were in an advanced state of rigor, meaning she likely died many hours before this photo was taken. remember, curtis said he tucked his sickly wife into bed only an hour before finding her dead. it didn't make sense to the officer. detective gibson went straight to his bosses with the old lovelace file. >> my first thought was, "we missed something here." >> reporter: chief robert copley had been in charge in 2006, when everyone assumed cory had died a natural death. but he says he never saw the photos the detective was now holding before him. >> and that's when i saw the pictures for the first time. >> reporter: what'd you think? >> i thought this -- this is odd. this is not natural -- >> reporter: the posture of the arms? >> the posture of the arms definitely, appeared to me that rigor mortis had set in. look at those pi