“Our heads aren’t in the sand,” Alejandro J. Beutel, the government and policy analyst for the Muslim Public Affairs Council, a national advocacy group, said at a forum his group sponsored on Monday on Capitol Hill. “The threat clearly exists, but I also want to put it in perspective. The threat exists, but it is not a pandemic.”  Fifty-one Muslim, civil rights and interfaith groups sent a letter last week to Speaker John A. Boehner, Republican of Ohio, and the House minority leader, Nancy Pelosi, Democrat of California, protesting Mr. King’s hearings as modern-day McCarthyism. They said that if Congress was going to investigate violent extremism, it should investigate extremists of all kinds and not just Muslims.  “Singling out a group of Americans for government scrutiny based on their faith is divisive and wrong,” said the letter, which was led by Muslim Advocates, a legal and policy organization in San Francisco, and was signed by non-Muslim groups including Amnesty International USA, the Interfaith Alliance and the Japanese American Citizens League.  Mr. Ellison said that while he would participate, “I’m going to make it clear that I challenge the premise of the hearings.  “If you put every single Muslim in the U.S. in jail, it wouldn’t have stopped Jared Loughner,” Mr. Ellison said, referring to the man accused of opening fire on an Arizona congresswoman and her constituents. “It wouldn’t have stopped the young man who killed his classmates at Virginia Tech. It wouldn’t have stopped the bombing in Oklahoma City or the man who killed a guard at the Holocaust Museum in Washington.”  But Mr. King dismissed this line of criticism, saying: “I totally reject that. That, to me, is political correctness at its worst. If we included these other violent events in the hearings, we’d be sending the false signal that we think there’s a security threat equivalency between Al Qaeda and the neo-Nazi movement, or Al Qaeda and gun groups. There is none.”  Mr. King added, “I’m not going to dilute the hearings by including other extremists.”  In fact, he said he planned to hold three or four more hearings this year on topics like the radicalization of Muslims in prisons and Saudi financing for American mosques.  He said the only witness he had settled on for certain of the three he would call in the first hearing was Dr. Zuhdi Jasser, a doctor from Arizona and an American military veteran who has little following among Muslims but has become a favorite of conservatives for his portrayal of American Muslim leaders as radical Islamists.  Mr. King said he had changed his mind about summoning as a witness Ayaan Hirsi Ali, a Somali-born feminist critic of Islam who became a member of Parliament in the Netherlands and then fled because of threats on her life.  The hearings, Mr. King said, would be organized into panels of witnesses, one of them to include members of Congress. He said Mr. Ellison would serve as a witness on that panel. He said he did not expect to call any of the local law enforcement or counterintelligence experts who he said had told him repeatedly that noncooperation by American Muslims is a “significant issue.” He says they will say these things privately, but not in public.  Some law enforcement experts have challenged Mr. King’s portrayal of widespread noncooperation. At the forum Monday, Sheriff Leroy Baca of Los Angeles County said he had cultivated extensive relationships with Muslim leaders throughout his county. He said that as a member of the Major City Chiefs Association, the Major County Sheriffs Association and the National Sheriffs Association, he had not heard complaints about noncooperation from Muslims.  Two other experts at the forum, Peter Bergen, director of the National Security Studies Program at the New America Foundation, and Roger Cressey, former director for transnational threats at the National Security Council, said the really sophisticated terrorists stop traveling and stop communicating in order to avoid detection. When that happens, they said, law enforcement must rely almost entirely on tips from the Muslim community to catch them.  A report issued last week by an independent research group on national security found that 48 of the 120 Muslims suspected of plotting domestic terrorist attacks since Sept. 11, 2001, were turned in by fellow Muslims, including parents, mosque members and even a Facebook friend. The report was issued by the Triangle Center on Terrorism and Homeland Security, which is affiliated with Duke and the University of North Carolina.  The report said, “In some communities, Muslim-Americans have been so concerned about extremists in their midst that they have turned in people who turned out to be undercover informants.”  A version of this article appears in print on February 8, 2011, on Page A18 of the New York edition with the headline: Muslims to Be Hearings’ Main Focus. Order Reprints| Today's Paper|Subscribe
The House Homeland Security Committee hearings on homegrown Islamic terrorism, which will be led by Representative Peter T. King of New York, have provoked an uproar from both the left and the right.