(CNN)
September 22, 2001 Posted: 1:13 p.m. EDT (1713 GMT)


An official has said there was definitely some shouting, but it is not clear who was in control of the plane before it crashed. Several family members of passengers have previously described cell phone conversations saying there might be an attempt to re-take control of the plane.

Officials say the voice recorder was able to pick up scuffling sounds.

Terrorists hijacked four commercial jets early on September 11. Two of them slammed into the World Trade Center's twin towers in New York, and a third hit the Pentagon in Washington.

But Flight 93 -- which departed Newark, New Jersey, en route to San Francisco, California, and turned around over Cleveland, Ohio, to head back toward the east -- never reached its target, which remains unknown.