The plane's left elevator, a tail part used to move the nose up and down, was found in three pieces, NTSB spokesperson Thomas Chapman said at a news conference Tuesday, the New York Post reports. The pieces were found about 1.3 to 3.8 miles from the crash site, the Post says.

“It tells us that at least some components, some pieces of the aircraft, important pieces of the aircraft separated before the impact,” Chapman said, the Post reports. He added that investigators did not yet know whether the loss of the piece caused the crash or was a result of the forces on the plane.

The Guardian reports that the tail pieces were found more than a mile from where the plane hit the ground. Chapman said the discovery confirms the plane was breaking apart before impact, The Guardian says. He said the plane could not have pulled out of its dive without the tail intact.

The jet was flying from Austin, Texas, to the Bahamas when it appears to have flown into a thunderstorm, The Guardian reports. Stormy weather at the time of the crash “remains a key focus of the investigation,” Chapman said, according to the Post.

In radio calls, co-pilot Nathalia Filgueiras, 20, reported icing and turbulence before the dive, The Guardian says. The jet crashed near a trailer park and exploded, the Post reports.

Relatives have named the victims as technology entrepreneur Adam Robinson, his wife Helen Sharp and their two young children, The Guardian reports. The Post says two family friends, a nanny, a veteran pilot and the co-pilot were also killed.

What we know: Tail pieces were found away from the crash site, which the NTSB says shows the plane was breaking apart in the air.
What we don't: What caused the plane to lose control. The NTSB says more analysis is needed.