The Learjet 60 involved in Sunday’s fatal crash in Palm Beach, Florida, may have broken apart before hitting the ground, according to preliminary information from U.S. air safety investigators.

The crash killed all nine people on board. At least one person on the ground was also injured.

The National Transportation Safety Board is investigating the circumstances surrounding the crash. The indication that the aircraft may have broken up before impact remains an early finding as investigators work to establish what happened.

Sources: Bloomberg Markets.