(BSS/AFP) - Weather conditions are a "major" focus of an investigation into a weekend private plane crash that killed nine people, US transportation investigators said Monday.

At a briefing, Tom Chapman of the National Transportation Safety Board, retraced the ill-fated journey of the Learjet 60, which departed Austin, Texas at 1537 GMT Sunday on a trip to North Eleuthera in the Bahamas.

The plane plummeted into a neighborhood in Palm Beach County in southern Florida, killing everyone on board.

The jet was carrying a pilot, a copilot and seven passengers. Authorities have not released their identities, saying genetic analysis is needed.

US media identified the copilot as 20-year-old Nathalia Gadelha Filgeiras, who had received her pilot`s license at age 17, before she received a driver`s license.

Filgeiras, who had already amassed 1,300 flight hours, began working for a charter plane company based in Fort Lauderdale, Florida about nine months ago.

Investigators have not determined yet who was flying the plane when it encountered trouble.

In an audio recording posted to air traffic website liveatc.net, someone in the cockpit can be heard reporting "moderate turbulence" and saying the crew was "managing the ice."

The person said the plane was "picking up precipitation" and needed "to climb" shortly before saying: "Mayday, mayday, we`re descending 10,000 feet per minute."

Chapman confirmed these statements had been made to air traffic controllers.

Aircraft maintenance records show there had previously been a cockpit recorder on the plane, but the NTSB doesn`t know if it was on the jet at the time of the crash, or if the agency will be able to recover it, Chapman said.

NTSB investigator Tim Monville said there was also an injury to a driver in the area near the crash site.

NTSB officials said the aircraft was flown by Aurora Aviation, which was operating as Upper Jets. Officials with the companies did not immediately respond to requests for comment from AFP.

The Bombardier plane went into service in 2004 and was renovated in 2018, according to Jettly.

The owner of the plane is listed as a Delaware company known as LR60271 LLC, according to the website of the US Federal Aviation Administration.