Video Key in Texas Student Murder Case

July 7, 2009 -- Employees arriving at Trans-Tech software company in Carrollton, Texas, the morning of Sept. 25, 2007, were greeted by the unthinkable.

Police Det. Greg Fraid was the first investigator to arrive on the scene.

"The call is a burnt body in a ditch and the body is charred beyond recognition," Fraid told ABC News' Jim Avila in a recent interview. "We were afraid it might be a serial killing, just the way the body was laid out in the ditch, it almost looked like it was posed, with her legs facing the parking lot and her knees kind of up. You can only tell it's a female by her hair and the French fingernail tips that she's had done. I've seen my share of terrible things people do to each other, and this one is probably the most horrific I've ever seen."

Police did not yet know that Melanie Goodwin, a sophomore communications major at the nearby University of North Texas, had gone missing the night before. They did not yet know that less than 12 hours earlier, Goodwin, 19, had stopped at a convenience store to pick up a snack for her boyfriend -- and encountered her terrible fate.

For part 1 of Melanie Goodwin's story, click HERE.

For all they did not yet know, police benefited from a crucial, immediate break in the case. The Trans-Tech parking lot was under round-the-clock video surveillance. Whatever happened to the young woman had happened on camera.

"You get excited, because you had a video which showed at an early morning hour a vehicle pulling up and somebody pulling the body out of the car, down to the ditch, back up to the car to get something out of the car, back down to where the body was, and you see a horrific burst of light, which is the flame and the body burning," Fraid said. "Person comes back up, jumps in the car and leaves."

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Police were able to identify the vehicle in the surveillance video: a red Saturn.

"I now have a vehicle I can look for," Fraid said of his thinking at the time. "There's an image which looks like a male. I've got a little bit of clothing that I can see from the video. You can see a white shirt, you can see half pants. Now you have hope that we can get a running start on something that we had nothing just a few moments ago."

Meanwhile, in a nearby suburb, Goodwin's boyfriend, Ale Valencia, was waking up in a panic. She hadn't arrived during the night as planned.

"I called and called and called and called," Valencia said. "I was trying to calm myself down, like you know, everything has to be OK. She's missing, missing -- and let's find her."