In 2002, Joseph Anthony Davis held up a 7-Eleven in Bremerton, Wash., with two plastic toy guns.
Nine years later, he sat in his SeaTac, Wash., apartment to plan a terrorist attack with machine guns and grenades against a Seattle military recruiting station, according to tape recordings made by an informant.
On June 22, federal officials arrested Davis, now known as Abu Khalid Abdul-Latif, as they once again unraveled an alleged plot developed not in some distant al-Qaida haven but by what appear to be homegrown radicals embracing a militant Islamic doctrine.
Terrorism analysts say such individuals have been involved in many of the Islamic terrorism cases prosecuted by the Justice Department in recent years.
And they caution that the United States is in a period of heightened risk for such plots, fueled by a combustible mix that includes graphic images of civilians killed by U.S. forces in Afghanistan, the upcoming 10th anniversary of the 9/11 attacks, and, perhaps most important, the U.S. special-operations team's killing of Osama bin Laden.
"With martyrdom comes a strong desire to retaliate. It adds another layer of motivation," said David Cid, executive director of the Oklahoma-based Memorial Institute for the Prevention of Terrorism. "Everybody has to be pretty much on their toes for the foreseeable future."
Law-enforcement officials in the Northwest and elsewhere in the nation also are on alert to potential terrorism threats from an expanding pool of American right-wing extremists.
"Just with the number of cases we've had in the past six months, I'm going to be asking for a 10 to 20 percent increase in our current (budget) numbers," said David Gomez, assistant special agent in charge of the FBI's Seattle office.
In recent years, terrorism analysts have spent a lot of time trying to better understand how people reach a point that they are willing to take such extreme action.
A 2007 New York Police Department study on homegrown terrorism found that most people involved in these plots began as "unremarkable" but were shaken by some event.
They then "gradually gravitate away from their old identity" and move into a more violent phase when they designate themselves as holy warriors.
Abdul-Latif seems to fit this pattern. He led a troubled life that included two suicide attempts and serving two years in prison for robbing the 7-Eleven, according to court documents. Either during or after his incarceration, he converted to Islam.
In recent months, as his efforts to run a cleaning-detailing business ended in a bankruptcy filing, Abdul-Latif emerged as a self-proclaimed "emir" in the alleged plot to attack the recruiting center.
An informant went to police and exposed the alleged Seattle conspirators. A Homeland Security Department study found that local residents or police initially detect 70 percent of terrorist plots. Local, state and federal law-enforcement officers share information through 70 "fusion centers," including one in the Seattle FBI office.
"The good news is that they work," said William Bratton, a former Los Angeles police chief who serves as vice chairman of a Homeland Security advisory committee.
Bratton said some terrorist plans have failed because the plotters were "not the brightest bulbs in the circuit." But it takes just one disturbed individual to create tremendous havoc.
In Seattle in 2006, Naveed Haq, a Tri-Cities man with a history of mental illness, attacked the Jewish Federation of Greater Seattle, making anti-Semitic statements before killing one woman and wounding five. In 2007, Maj. Nidal Malik Hasan, an Army psychiatrist who appeared to have been influenced by the Internet preachings of a jihadist in the Middle East, killed 13 people and wounded 32 in an attack at Fort Hood, Texas.
The threat of violence from right-wing extremists also has surged during the past several years, according to Cid, the head of the Oklahoma terrorism-prevention institute. He says the current threat level is similar to the months before the 1995 Oklahoma City federal building bombing by Timothy McVeigh, which killed 168 people, including 19 children.
"We are seeing the rhetoric on the webpages become more pointed ... and we are concerned," said Cid, a former FBI agent who assisted in the investigation of the Oklahoma City bombing.
In 2010, the Southern Poverty Law Center identified 824 militia groups, a big spike from the 149 counted in 2008.
Militants are rallying around issues such as immigration and fears of a changing American demographic that is predicted to put whites in a minority around 2050, according to Mark Potok of the center. The election of the biracial President Obama has also played to their fears.
This year, a man with ties to a neo-Nazi group was arrested in Arizona for allegedly building homemade grenades and pipe bombs to supply groups patrolling the Mexico border. In March, six people with a cache of weapons that included grenades and grenade launchers were charged with plotting to kill or kidnap Alaska state troopers and a Fairbanks judge.
"It gets to the point that ideology is less important than action," said Gomez, the FBI assistant special agent in charge in Seattle. "From my perspective, it doesn't matter if it's Christian Identity or radical Islam. We have to focus on these guys committing crimes."