Videos bring back happy memories of Mary Nielsen's two children. "Teddy was just so sweet and loving. He was a mama's boy, you know," Nielsen said, "Emmy was exceptionally smart. She just had turned 5 in January, and you wouldn't have known it." Sign up for our Newsletters Now these memories are all Nielsen has, after her two children were found dead in their father's Bellevue home last month. "They had like a special bond, like, they were very,...