Doug

Doug was a newborn vampire from Victoria's Seattle newborn army. He was mentioned in The Short Second Life of Bree Tanner by Bree when Diego told her that indirect sunlight doesn't harm them. Bree thought it was impossible and said, "But Shelly and Steve. Doug and Adam. That kid with the bright red hair. All of them. They're gone because they didn't get back in time. Riley saw the ashes."

It was officially confirmed in The Twilight Saga: The Official Illustrated Guide that Doug was the first to discover that the sun did not hurt vampires, and was killed by Victoria after telling Riley about his discovery.