Several years ago Osama bin Laden’s second in command, Ayman Al Zawahiri, said that Al Qaeda wants American operatives. They now have some.

There are a growing number of Americans who, despite enjoying the benefits of freedom and rule of law, choose to become terrorists, bent on killing their countrymen, destroying property, and if necessary, dying in the process. They pose a unique danger because impressionable and misguided Americans can plan and execute attacks in anonymity more effectively than their non-American terrorist brethren. They represent the “nightmare” threat scenario.

Radicalized Americans have been involved in more than a dozen homegrown terrorist plots in the last 18 months. Suspects have been arrested in schemes to blow up New York subways; in conspiracies to provide material support to terrorists; and in plots to kill people overseas. And the hunt continues for high-value American Al Qaeda operatives Adam Gadahn from California, Omar Hammami from Alabama and Anwar Al Awlaki from New Mexico. All of them have ties to these plots and Al Qaeda operatives throughout the world.

Identifying homegrown terrorists before they commit atrocities requires widespread public participation. This month, two New Jersey men were arrested at JFK airport, planning to travel to Somalia to "wage violent jihad." They also had expressed a willingness to commit violent acts in the United States. Both men were American citizens. The FBI received a tip regarding the men's activities in October 2006. In the intelligence community, that tip is called a “SAR” – Suspicious Activity Report.

The National SAR Initiative was created to establish formal standards for reporting suspicious activity and information sharing between law enforcement agencies. SARs contain information that might suggest terrorist or other criminal planning or intelligence gathering activity. Alert citizens who notice suspicious activity possess critical knowledge, and this information can be used to uncover potential threats, if shared with the proper authorities.

Appropriately, privacy and civil liberty protections are critical SAR requirements. We have a duty to ensure that our policies against alleged criminals do not harm or alienate innocent people. In furtherance of these protections, SARs inherently support objective analysis. They are centered on activity; behavior is the driver, not race, nationality or religion.

Enhancing the SAR effort, the Los Angeles Police Department recently launched “iWatch.” This community initiative educates the public about suspicious behaviors and how to report them. A simple phone call or report may lead to actions that disrupt a terrorist attack. The iWatch program, easily adaptable to other municipalities, is expected to spread nationwide.

Academic efforts are taking the fight to the next level with “iSARs” or integrated SARs.  The iSARs process involves interdisciplinary research designed to explore software-based decision support tools for intelligence analysts. Real time data analysis allows SARs to be evaluated, determining their significance as actionable intelligence and whether law enforcement investigation is warranted.

Al Qaeda has survived for more than two decades because it is adaptable and versatile. Its plots have evolved to emphasize speed and probability of success over spectacle. It has stopped launching simultaneous attacks, and it is using fewer attackers. Using untrained operatives, however, has cost it. The attempted attacks on Northwest flight 253 last Christmas and in Times Square in May were unsuccessful only because the operatives failed. They will try again.

To disrupt their strategies, we are reverse-engineering the terror planning cycle. Analyzing SARs and social networks tells us how terrorists organize, how they plan, how they communicate and how they are financed. As our learning curve shortens, attackers will be forced to expend time, energy and resources to avoid detection. They will exist in a hostile environment, complicating their planning efforts.

Critical observations reported by engaged citizens throughout the country assist law enforcement and homeland security officials to identify those who would do us harm – the Al Qaeda operatives hiding in plain sight. Homeland security is everybody’s business. It starts with you.

Erroll G. Southers is the associate director of the DHS National Center for Risk and Economic Analysis of Terrorism Events (CREATE) and adjunct professor of homeland security and public policy at the University of Southern California. He is also the Managing Director of Counter-Terrorism and Infrastructure Protection for TAL Global Corporation.