The executive director of the independent commission investigating the Sept. 11, 2001, terrorist attacks has become a witness in the inquiry and has been interviewed by his own staff about his involvement in shaping the Bush administration’s early counterterrorism strategy, officials said on Wednesday. In addition, one of the 10 commissioners on the panel, a deputy attorney general in the Clinton administration, was also interviewed this week. The unusual dual roles of the director, Philip D. Zelikow, and the commissioner, Jamie S. Gorelick, have raised fresh questions about potential conflicts of interest in the commission, which has been dogged by concerns about its independence since it was created in 2002. Full Story