MOUNTLAKE TERRACE — Earlier this month, Theresa Kauffmann and her husband, Mark, were sitting in their living room when they heard an unusual noise outside.

It was kind of a repeating, whooshing sound — “whoowhoowhoowhoo,” is how Theresa Kauffmann described it.

“It got louder, louder and it got really loud,” she said.

Finally, “it went ‘BANG!’ into the roof and then it slid down and it banged onto the deck.”

The “it” was a thin panel of metal, nearly square with straight edges, about 23 by 18 inches. It was shiny black on one side, shiny white on the other.

Her neighbor was outside and heard the object fall, though he didn’t see it, Kauffmann said.

“Someone could have been clocked with that thing,” she said.

Figuring it must have come from an aircraft, she immediately called Paine Field and someone arrived within a half-hour to pick it up, she said.

“We have no idea what it is,” airport director Dave Waggoner said.

Paine Field officials showed it to staff at Regal Air, which runs an aircraft maintenance operation at the airport.

Officials were told it didn’t come from an airplane, Waggoner said.

“‘This is not an aviation piece of equipment,'” he said in recounting the response from Regal Air.

Still, Waggoner said Paine Field flight records for that evening, Feb. 9, were checked. Only one plane was found to have taken a flight pattern near Mountlake Terrace around the time of the incident, shortly after 7 p.m., he said.

The owners of the light, twin-engine aircraft were contacted and said nothing was missing from their plane.

It’s also highly unlikely it could have been thrown through an airplane window or come off a jetliner headed for Sea-Tac International Airport or Boeing Field, Waggoner said.

“It’s kind of the size of an airplane window,” he said. “And it’s not the kind of thing a jetliner would be carrying.”

Kauffmann said she and Mark live in a fourplex set back from the street nearly a quarter-mile from I-5, so it’s not likely the object came from a vehicle, she said. Also, there are no tall evergreens near their house, so it probably did not fall from a tree.

Weather records showed the wind was calm that night, Waggoner added, so it doesn’t appear the object was picked up by a gust and carried to the Kauffmanns’ home.

“That’s why it’s such a mystery,” he said.

Kauffmann still wants to know what it is.

“It’s not every day that something falls out of the sky like that,” she said. “I think we should have a right to know when things fall out of the sky what they are.”

Bill Sheets: 425-339-3439; sheets@heraldnet.com.