More survivors of an Oregon bus crash that killed that killed nine passengers have joined a lawsuit filed in Tacoma, Wash., by two teenage victims.

The amended complaint filed Wednesday by attorney Charles Herrmann adds the president of Mi Joo Tour & Travel and the driver as defendants. The suit says they engaged in willful misconduct.

The tour company based in Vancouver, British Columbia, also faces a lawsuit filed by a Canadian couple alleging the bus was defective. Both suits seek unspecified damages.

Police have yet to say what caused the Dec. 30 crash near Pendleton, but both the U.S. and Canadian governments have banned the company from operating buses.

Company attorney Mark Scheer says black ice was a major factor in the bus losing control.