died at 13 years old. german shepherd was rescued as a puppy in 2008. the president and first lady released a statement saying that their hearts are heavy and he will always be missed. now back to dateline. now back to dateline ♪ ♪ ♪ >> welcome back to dateline. i'm natalie morales. three years after sandra galas murder, the investigation had stalled. and her chief daryl perry, like sanders father larry, chief perry knew the pain of losing a child. motivated by their shared grief, he asked state investigators to take a look at the file, and remarkably, they found new evidence. but in a case full of twists, there was another one just around the corner. here again is keith morrison with the other side of paradise. >> it took a scientific breakthrough to finally get