A small, private jet crashed into a house in Maryland's Montgomery County Monday, killing at least three persons on board and a mother and her two young sons inside the home.

The victims on the ground were identified as 36-year-old Marie Gemmell and her two sons, 3-year-old Cole and a 1-month-old Devon, police said.They were found in a second-floor bathroom.

Gemmell was lying on top of her young sons in an apparent effort to shield them from the smoke and fire, said police Capt. Paul Starks. Her husband and a school-age daughter were not home and were accounted for, police said.

Health Decisions of Durham, North Carolina said in a news release that Dr. Michael Rosenberg, founder and CEO of the clinical research organization, was among those killed.

Rosenberg was a pilot who crashed a different plane in Gaithersburg on March 1 2010, The Associated Press reported, quoting a government official who wasn't authorized to speak publicly and asked not to be named. Investigators are still trying to determine if Rosenberg was at the controls at the time of Monday's crash.

Fred Pedreira, 67, who lives near the crash site, said he had just returned home from the grocery store and was parking his car when he saw the jet and immediately knew something was wrong.

"This guy, when I saw him, for a fast jet with the wheels down, I said, `I think he's coming in too low,"' Pedreira told The Associated Press. "Then he was 90 degrees -- sideways -- and then he went belly-up into the house and it was a ball of fire. It was terrible.

"I tell you, I got goosebumps when I saw it. I said, `My God, those are people in that plane," Pedreira said. "I just hope nobody was in that home."

At least three people on the plane didn't survive the crash into the home in Gaithersburg, a Washington, D.C. suburb, said Pete Piringer, a Montgomery County Fire and Rescue spokesman.

Piringer said a fourth person may have been aboard.

Piringer said the jet crashed into one home around 11 a.m., setting it and two others on fire. Crews had the fire under control within an hour and were searching for anyone who may have been in the homes.

Byron Valencia, 31, who also lives nearby, told The AP that he was in his kitchen when he heard a jet engine flying overhead, and then a big thump shortly after.

"When I opened my window, I could see smoke over the trees and I heard a small explosion, like a pop," he said. "I could see the smoke rising ... It's scary."

Emily Gradwohl, 22, who lives two doors down from the house the jet hit, was home at the time of the crash and ran outside to see what had happened.

"I heard like a loud crash, and the whole house just shook," Gradwohl told The AP. "We got jackets on, ran outside and saw one of the houses completely set on fire."

She said planes fly low over the neighborhood every day but she had never worried about a crash until now.

An FAA spokesman said preliminary information shows the Embraer EMB-500/Phenom 100 twin-engine jet was on approach at the nearby Montgomery County Airpark. The National Transportation Safety Board is sending an investigator to the scene.

The Associated Press contributed to this report.

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