It was the sound of the engine that alerted some people who were in Seattle's Fisher Plaza Tuesday morning that something was amiss. At about 7:40 a.m., Bo Bain was a few feet from the famed Space Needle that towers over the northern end of the city when he heard sounds he has grown accustomed to hearing during his work in the tourist district on a construction project.

"We were working here on the corner and the helicopter came in and landed, as he usually does several times a day," Bain told CNN affiliate KOMO. The pilot put the news helicopter down on a landing pad outside KOMO's offices "for a minute or two," and then tried to rise again into the air, Bain said. That's when the routine engine noises changed abruptly, and Bain knew something was up.

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