Law enforcement officials identified the gunman as James W von Brunn, who embraces various conspiracy theories involving Jews, Blacks and other minority groups and at one point waged a personal war with the federal government.
The gunman and the security guard were both taken to the nearby George Washington University Hospital on Wednesday, Jun 10
According to a high ranking police source, Von Brunn was shot in the face, and the bullet exited from his neck. He underwent surgery and was described as being in critical condition.
Police recovered a notebook in the suspect's possession that apparently contained a list of district of Columbia locations, including Washington National Cathedral.
Von Brunn is said to have been a leading writer in the white supremacist fringe for many years. He also appears to be the author of a recent Internet posting suggesting that President Obama's background is being hidden from the public.
His online book, 'Kill the Best Gentiles', contains hundreds of pages of conspiracy theories that include Holocaust denial.