Even thought the FBI was "aware" of alleged Holocaust Memorial Museum gunman James von Brunn and his history of hateful racist writings, authorities had not opened a criminal investigation of him before Wednesday's deadly attack - a scenario that underscores the challenge the rising tide of Internet-based white supremacists poses to law enforcement.
In the wake of the attack, authorities from the Department of Homeland Security to police in New York City and Los Angeles asked for help from Jewish leaders and maintained heightened patrols Thursday around synagogues and universities.
In an e-mail alert to state and local agencies Wednesday after the fatal shooting of a guard at the Holocaust Museum, Homeland Security and FBI wrote, "This appears to be an isolated incident" involving a lone suspect, and that authorities had no additional information to indicate threats to area landmarks. In another alert, the agencies said von Brunn was associated with right-wing extremism.
Within the past three months, solo shooters with political motivations have launched attacks in a Little Rock, Ark., armed services recruiting station, a Kansas church attended by an abortion provider and against police in Pennsylvania, killing five and raising questions about the danger posed by U.S. radicals.
Nonetheless, Secretary of Homeland Security Janet Napolitano was criticized by conservatives in April with the leaking of an intelligence report that warned police to be on guard for recruiting during the recession by right-wing extremist groups.
In San Francisco on Thursday, Napolitano said the report had been poorly written but that its fundamental point was valid. She would not say that the Holocaust Museum shooting vindicated the report.
"Violence can erupt in a lot of different ways in society," she said. "The problem of the so-called 'lone wolf' is seen most frequently at the local level. And circumstances are such that they can lead to increased violence, including a down economy among other things."
Activists and advocates for Jewish causes mostly praised the quick response Wednesday afternoon of law enforcement agencies who responded to Wednesday's attack.
But David Friedman, the Washington regional director of the Anti-Defamation League, added Thursday: "We don't have an ocean separating us from the extremists who represent the kind of hatred unleashed yesterday. They live among us. They can pick their time for the most part, not having to worry about whether they have documentation. ... People like von Brunn were not apparently acting in a way that would cause them to be the subject of a criminal investigation."
Law enforcement agencies already had stepped up their efforts to track domestic extremists last year, a drive that intensified after the election of the first black president and the widening of economic troubles that can present recruiting opportunities to militia groups.
Jack Levin, a criminologist at Northeastern University who has written widely about hate crimes, said the white supremacist movement has changed in profound ways since the 1990s. Charismatic leaders of the largest groups have gone to prison or died in recent years, producing more lone wolves and splinter cells who recruit new members using the Internet.
"It has become more difficult for the FBI and other federal agents who want to infiltrate these groups or even keep an eye on them," Levin said.
Chronicle staff writer Tyche Hendricks contributed to this report.
