OWATONNA, Minn. (AP) - National Transportation Safety Board investigators haven't focused on any single issue yet as they seek the cause of the corporate jet crash that killed eight people, a board member said Saturday.

"We are looking at everything," said board member Steven Chealander. "There is no single focus at this point. It is a multiple focus accident investigation."

The plane was carrying six casino and construction executives and two pilots when it went down Thursday, killing everyone on board. The executives were coming to Owatonna to meet with representatives of a local glass company called Viracon to discuss a $2 billion hotel-casino complex being built in Atlantic City, N.J., by Revel Entertainment.

The chartered aircraft went down in a cornfield northwest of Degner Regional Airport. Seven people were found dead at the site; the eighth died at a hospital.

The victims include East Coast Jets Inc. pilots Clark Keefer, 40, of Bethlehem, Pa., and Dan D'Ambrosio, 27, of Hellertown, Pa. D'Ambrosio's mother had long feared such a crash.

"I never once doubted his prowess," Marcia D'Ambrosio of Allentown, Pa., said Friday. "But deep down in my gut, I just knew he was going to die in a plane crash."

Investigators plan to interview crash witnesses as well as people in Pennsylvania where the flight originated and in Atlantic City where it stopped, Chealander said.

They also are looking at runway conditions, mechanical issues and a thunderstorm that moved through the area before the crash, he said.