The Pentagon Metro station sits beneath one of the most heavily defended buildings in the world. The checkpoint where Bedell was challenged that night was outside the secured perimeter, where Force Protection officers check credentials of anyone trying to enter the building through the transit-system entrance. He had two 9mm semiautomatic pistols on him and several loaded magazines. More ammunition was found in his car parked in a nearby garage. He did not run. He did not shout. He raised a weapon at officers who had stopped him for routine identification and started shooting. Officer Amos was hit in the shoulder. Officer Carraway in the thigh. Both returned fire. A third officer who heard the gunfire ran in to support them. Bedell was struck in the head and went down. Chief Richard Keevill of the Pentagon Force Protection Agency would later say that the conflict was over in less than a minute. The wounded officers were treated at George Washington University Hospital and released that night. Bedell was taken to the same hospital. He died there the next day.

John Patrick Bedell grew up in Hollister, California, a town of about 35,000 in San Benito County between the coastal range and the Salinas Valley. He graduated from UC Santa Cruz in 1994 with an undergraduate physics degree, then drifted - a year of biochemistry at San Jose State in 1995, periods of work in tech and circuit design, periods of unemployment, a 2006 arrest in Orange County on marijuana cultivation charges. He had been diagnosed with bipolar disorder, possibly schizophrenia, sometime before the 2006 arrest, according to an Orange County court filing. He returned to San Jose State in 2009 for a graduate program in electrical engineering. A professor there called him one of the best circuit design students in the class. He kept a blog called Rothbardix, named for the anarcho-capitalist economist Murray Rothbard. The blog argued for protection of private property and against modern government as such. It also revealed a deepening paranoia about what he called the violent seizure of the United States government, the September 11 demolitions, and a coup regime of 1963 that maintains itself in power through the global drug trade, financial corruption, and murder.

One thread ran through Bedell's writing in the months before the attack: the 1991 death of Marine Corps Colonel James E. Sabow at his quarters at the El Toro Marine Corps Air Station in California. The official ruling on Sabow's death was suicide. A small but persistent community of family members and conspiracy theorists has argued for decades that Sabow was murdered to cover up military drug-trafficking operations. Bedell apparently became obsessed with the case. He wrote on a Wikipedia page that bringing attention to what he called military corruption would see that justice is served in the death of Colonel James Sabow. He linked the Sabow theory to the September 11 attacks, which he believed had been carried out by the U.S. government, and to a broader vision of a cannabis-based monetary system that would require billions and billions of carefully cultivated, highly valuable cannabis plants growing through the United States with complete security of property. His blog posts had grown more frantic in the weeks before March 4. His parents, alarmed by his deterioration, had warned police in California a few days earlier that he might be a danger to himself or others. He had already left the state.

In the days after the shooting, journalists tried to fit Bedell into a familiar political frame and could not. The Christian Science Monitor noted that he was a registered Democrat who had been anti-Bush, but argued it would be facile to call him left-wing. He had also embraced anarcho-capitalist libertarianism, conspiracy theories about a 1963 coup, and an open insurgent project he had proposed on Google Code that would integrate existing open-source codebases to create a massively multiplayer online roleplaying simulation of low-cost defenses against modern military opponents. The Monitor grouped him with what it called non-partisan or post-partisan anti-government extremists - a category that included Joseph Andrew Stack, who had flown a small plane into an IRS building in Austin three weeks earlier, killing himself and an IRS manager. Bedell's actions are sometimes cited as terrorism. They are sometimes cited as a mental health crisis. They are usually cited as both. Officers Amos and Carraway returned to duty. The Pentagon checkpoint operates the same way it did before the shooting, with the same procedures, in the same place. Most evenings the commuters streaming through it do not look up.