According to the news station, the chopper was lifting off from its roof when it went down at a busy downtown intersection and crashed into three cars on Broad Street. The helicopter and cars quickly became engulfed in flames. After the smoke cleared, only the tail of the helicopter could be identified among the burned metal.
"I saw the whole thing. I saw the helicopter coming down. I didn't want to believe what I was seeing at first," said Michael Hawthorne, a witness.
Two people on board the plane were declared dead at the scene. They were identified as photographer Bill Strothman and pilot Gary Pfitzner. Strothman had recently retired from the station and was only working part-time in the chopper so that he could spend more time with his family.
A federal official said witnesses reported hearing unusual noises from the helicopter before it crashed. Officials said the helicopter did not hit any buildings as it went down.
"This is a blow to us internally, though they were not our employees, we consider them family," said KOMO-TV News Director Holly Gauntt.
One man managed to free himself from his vehicle and was rushed to Harborview Medical Center with critical injuries. Richard Newman, 38, suffered burns on his lower back and arm, covering up to 20 percent of his body, hospital spokeswoman Susan Gregg said. He was in serious condition in the intensive care unit and likely will require surgery, she said. Two other drivers whose cars were hit by the chopper escaped unharmed.
KOMO says the chopper that crashed was actually the station's backup. The regular news helicopter is undergoing repairs.
Officials with the National Transportation Safety Board responded to the scene. Investigators are searching for any possible surveillance video in the area that might have captured the crash. Officials say the crash site could be closed for three to five days during the investigation.
The Associated Press contributed to this report.