Mr. Bedell wrote on the Web that he was “determined to see that justice is served” in the death of Colonel Sabow and that to uncover the truth behind the death would be “a step toward establishing the truth of events such as the Sept. 11 demolitions.”

The police said they had ruled out the possibility of a second gunman even though they saw Mr. Bedell, who was killed in an exchange of gunfire, speaking to someone before firing on the officers. Federal authorities also said there was no indication that Mr. Bedell had a connection to any domestic or international terrorist group.

After searching Mr. Bedell’s green Toyota, which was parked at a nearby shopping mall, the police found additional ammunition and signs that he had driven in the past several weeks from Hollister, Calif., where he was living. “We are devastated as a family by the news from yesterday,” Mr. Bedell’s parents said in a statement Friday. “To the outside world, this tragedy is the first and only thing they will know of Patrick.”

“To us, he was a beloved son, brother, grandson, nephew and cousin,” they said. “We may never know why he made this terrible decision. One thing is clear though: his actions were caused by an illness and not a defective character.”

His mother, Kaye Bedell, is the director of allied health at Gavilan College, and his father, John Bedell Sr., is a financial planner in Hollister.

When he appeared at the Pentagon on Thursday around 6 p.m., Mr. Bedell had a full beard and was dressed in a blazer, slacks and a white collared shirt, and surveillance cameras showed him walking slowly toward the Pentagon entrance before pulling out two 9-millimeter semiautomatic weapons. He began shooting when he arrived at the security checkpoint, near the entrance to the Pentagon subway station.

Officers Jeffrey Amos and Marvin Carraway were superficially wounded, one in the shoulder and one in the thigh, according to the police.