WASHINGTON – A gunman coolly drew a weapon from his pocket and opened fire at a security checkpoint into the Pentagon on Thursday in a point-blank attack that wounded two police officers before the suspect was fatally shot.

The two officers suffered grazing wounds and were being treated in a hospital, said Richard Keevill, chief of Pentagon police. The shooter, identified as John Patrick Bedell, 36, of California, died hours after being admitted to a hospital in critical condition, authorities said. They had no motive for the shooting.

There were signs, however, that Bedell may have harbored resentment for the military and had doubts about the facts behind the Sept. 11 terrorist attacks.

In an Internet posting, a user by the name JPatrickBedell wrote that he was “determined to see that justice is served” in the death of Marine Col. James Sabow, who was found dead in the backyard of his California home in 1991. The death was ruled a suicide but the case has long been the source of theories of a coverup.

The user named JPatrickBedell wrote the Sabow case was “a step toward establishing the truth of events such as the September 11 demolitions.”

That same posting railed against the government’s enforcement of marijuana laws and included links to the author’s 2006 court case in Orange County, Calif., for cultivating marijuana and resisting a police officer. Court records available online show the date of birth on the case mentioned by the user JPatrickBedell matches that of the John Patrick Bedell suspected in the shooting.

The shooter walked up to the checkpoint at the Pentagon’s subway entrance in an apparent attempt to get inside the massively fortified Defense Department headquarters. “He just reached in his pocket, pulled out a gun and started shooting” no more than five feet away, Keevill said. “He walked up very cool. He had no real emotion on his face.” The Pentagon officers returned fire with semiautomatic weapons.

The subway station is immediately adjacent to the Pentagon building, a five-sided northern Virginia colossus across the Potomac River from Washington. Since a redesign following the 2001 terrorist attack on the Pentagon, riders can no longer disembark directly into the building. Riders take a long escalator ride to the surface from the underground station, then pass through a security check outside the doors of the building, where further security awaits.