HARTSVILLE, S.C. -- Federal investigators say it appeared someone on a plane that crashed earlier this month in Hartsville had opened a panel inside the aircraft that accesses the landing gear.

The plane crashed March 8, killing all three people on board.

The National Transportation Safety Board released a preliminary report on the crash Tuesday. The report says the pilot had pulled a handle for the landing gear into the down position, but the nose gear remained up and the rear gear was not all the way down.

The report says an access panel to the landing gear controls was exposed under a seat. The door had scratch marks on top and a jackknife was found nearby.

The preliminary report did not give a cause for the crash of the experimental turboprop plane.