The agency said investigators recovered and identified portions of the aircraft and have sent them for inspection. The impact site, where the crash left a large crater, remains under investigation.

The plane went down on Nov. 1 in Greenacres, roughly seven miles southwest of West Palm Beach. Thick black smoke poured from the wreckage, and little of the aircraft remained intact after the nose-dive into the neighborhood.

Radio transmissions captured in the final moments show the co-pilot, 20-year-old Nathalia Gadelha Filgueiras, calmly reporting ice buildup as the jet flew into a thunderstorm. She told air traffic controllers the aircraft was being tossed up and down by turbulence of about 700 feet before the situation deteriorated rapidly.

"Declare an emergency 722-Bravo-Delta. We are in an overspeed condition descending 20,000 feet per minute!" she said, according to the transmissions.

The victims included the pilot, 55-year-old Jeff Gregory, and Filgueiras, who handled the last communications with controllers. Also killed were technology entrepreneur Adam Robinson; his wife, Helen Sharp; their two young children; two friends of the couple; and the children's nanny.

About 600 residents near the crash site were displaced, though only one ground injury was reported. A shelter was set up for residents of nearly 80 mobile homes close to the impact zone.

The crash has shaken a working-class neighborhood and raised questions about severe-weather flying and the risks that general aviation can pose to communities below. The NTSB's findings will be closely watched by residents and local officials as the agency works to determine what caused the jet to go down.

A preliminary report is expected in the coming weeks, though a final determination of probable cause typically takes a year or more.