Beefed up ties between U.S. law enforcement and communities nationwide are needed to help prevent terror strikes by homegrown militants, former Congresswoman Jane Harman told Xinhua in an interview.

Harman, who served on all the major Congressional security committees -- Armed Services, Intelligence and Homeland Security -- during her nine terms in Congress, said thwarting homegrown violent militancy requires building trust "not only in Muslim communities, (but any communities) where there are disaffected immigrants or (non-immigrants)."

Those sentiments come two weeks after twin bombs killed three and wounded nearly 300 in the most deadly terror strike on U.S. soil since the Sept. 11, 2001 attacks on New York and Washington. While it remains unknown whether the suspects -- 19-year-old Dzhokhar Tsarnaev and 26-year-old Tamerlan Tsarnaev -- had direct ties to terror groups, reports indicate the brothers were influenced by radical Islamic ideology.

Touting New York City's program that employs 1,000 intelligence officers to combat terrorism, Harman noted the officers "work with communities and look for signs of behavior changes."

Harman said one sign that would have red-flagged older brother Tamerlan, had he lived in New York, was a January outburst during Friday prayer services in a Boston area mosque that, according to some reports, got him thrown out of the service.

The bombing suspect allegedly shocked the congregation by shouting at the imam for touting U.S. civil rights leader Martin Luther King Jr. as a role model for Muslims. Tamerlan objected on grounds that King was not a Muslim, according to initial reports in the Los Angeles Times.

"The changes in his behavior would have been enough to alert the New York Police Department to pay attention to him," said Harman, now the president of the Washington-based Woodrow Wilson Center.

Some U.S. media reports published last year, however, blasted New York' s intelligence program for what were called "systematic spying" on Muslim neighborhoods and photographing law abiding citizens -- even when there was no evidence against them. But Harman emphasized that community building should uphold constitutional rights and maintained Muslims should not be singled out. Her comments were not related to the media reports.

She also praised the Los Angeles County Sheriff's Advisory Councils -- an ongoing partnership with representatives of that area's ethnic groups that regularly meet to keep authorities apprised of issues that impact their communities and advise law enforcement on being sensitive to their customs and beliefs.

Such community building is needed "so that family members or people in their mosques or churches or their schools notice (potentially violent) behavior and alert the appropriate people," she said.

Recalling the 2009 arrest of five men from the suburbs of Washington D.C. who allegedly traveled to Pakistan to attend al-Qaida-led terror training camps, Harman noted that their families in the United States had alerted authorities in a move that led to their arrest in Pakistan.

"(The arrests) never would have happened if their families hadn't trusted law enforcement," she said.

Harman emphasized that while even radical beliefs are protected under the U.S. constitution, it is when those beliefs spark violent action that authorities and communities must be on the lookout.

"The problem is finding that grey area...where somebody with radical beliefs makes the decision to commit violent acts," she said. "And that is the place where you want to intervene."

Avoiding the perception that Muslim communities are singled out, however, is "tricky -- you have to build trust," she said. "You have to have meetings (with community leaders)."

The same goes for any community, she added.

"Pick any community -- you can't just say 'I want the Chinese community in Washington D.C. to trust me.' Forget it. That's not going to happen. You have to convene a meeting and you have to talk about what your goals are and (identify) shared goals (with community leaders)," she said.

Recalling the 1995 Oklahoma City bombing by right-wing extremist Timothy McVeigh that killed nearly 200 people, she said any disaffected person is capable of committing horrific acts of terror.

Homegrown militant Islam has emerged in recent years amid intense U.S.-led pressure on al-Qaida and its splinter groups worldwide, which led to the killing of terror mastermind Osama bin Laden and the decimation of the organization's core leadership.

Muslim terrorists often isolate themselves from their communities, becoming highly critical of mainstream mosques, most of which condemn violent militancy.