It's too early to know if this is a case of pilot error, mechanical error or a combination of both.
But recently released amateur video of the crash may help lead to answers. (See above).
Investigators are lucky. They have lots of evidence.
Flight data and cockpit voice recorders, pilots who are alive, and the video may explain a lot.
Local aviation expert and pilot John Nance can point out several glaring problems with the aircraft's landing approach.
"He was probably doing a 100 knots when he should have been doing a 130," Nance said. "The airplane was coming in nose high and that was unusual; he's also way low,"
Nance estimates the plane at this point is about 100 feet above the surface when it should be more like 300 feet.
And the nose rises higher just before impact.
"The only reason a crew would be doing this is they don't have enough power to sustain flight. He's trying to eek out everything he has left in terms of energy," Nance said.
While investigators search for answers, people here in Seattle struggle with the ripple effect of Saturday's accident.
Seattle's Korean-American community is trying to find out as much as possible.
Bee-Young Kim is a deacon at Seattle First Korean Church, where so far, no members are known to have been onboard.
"We're going to have a lot of explaining to do with our relatives in Korea," Kim said. "We are partially relieved but we're also keeping our prayers for those folks."
Nance, the aviation expert, said it's extremely fortunate that plane eventually landed on its belly.
"If it had gone all the way over we most likely would have lost a lot of people," he said.