Updated

The mosque where at least one of the two suspected Boston Marathon bombers prayed has a controversial history, with ties to the Muslim Brotherhood, terror funding and frequent fiery sermons, according to a group that has long monitored the house of worship.

“This is a radical mosque,” Dennis Hale, of a Boston-based group called Americans for Peace and Tolerance, said of the Islamic Society of Boston.

No one from the law enforcement community has publicly suggested that the mosque, located in the brothers' Cambridge neighborhood, played any official role in radicalizing either Tamerlan Tsarnaev or his younger brother, Dzhokhar Tsarnaev.  But Hale, also a professor of political science at Boston College, said there's reason for concern.

[pullquote]

The mosque’s founders were in the Muslim Brotherhood and one, Abdurahman Alamoudi, pled guilty in 2004 for conducting illegal transactions with the Libyan government and his partial role in a conspiracy to assassinate Saudi Crown Prince Abdullah, Hale said. Alamoudi, who served as an Islamic adviser to President Clinton, was accused by critics of espousing pro-American language while lobbying in Washington, while expressing his support of terror groups Hamas and Hezbollah when addressing Islamist rallies.

More On This...

    Sheikh Ahmed Mansour, who has served on the APT board with Hale and founded the Quranists sect of Islam, leading to his eventual exile from his native Egypt, told FoxNews.com that the rhetoric at the Cambridge mosque gave him a bad feeling.

    "I was astonished seeing that this mosque, at the time I was there, was controlled by fanatics," he said, recalling how he attended sunset prayers one Friday while he was a visiting fellow at Harvard Law School. "Their writings and teachings were fanatical. I left and refused to go back to pray. I left Egypt to escape the Muslim Brotherhood, but I had found it there."

    Mansour said fiery sermons can spur impressionable young men to violence, even if the speaker doesn't explicitly advocate it.

    "These terrorists who kill are victimized by the sheiks. So the criminal are the sheiks," he said. "This mosque continues to increase fanaticism among Muslims."

    Among the controversial figures associated with Islamic Society of Boston, which runs the mosque Tamerlan Tsarnaev attended:

    — In March 2010, Imam Abdullah Faarooq gave a sermon praising Aafia Siddiqui, an MIT graduate who had returned to her native Pakistan in 2003 and was later exposed as courier and financier for Al Qaeda. She was eventually arrested in Afghanistan with containers of sodium cyanide and notes on making a bomb. In his sermon, Faarooq proclaimed Siddiqui's innocence and told worshippers, "You must grab on to this rope, grab on to the typewriter, grab on to the shovel, grab on to the gun and the sword, don't be afraid to step out into this world and do your job."

    — Yusuf Al-Qaradawi, an original trustee of the Islamic Society of Boston and known as the spiritual leader of the Muslim Brotherhood. In the past, he has told followers in sermons that Jews and homosexuals should be "exterminated.” The Anti-Defamation League has referred to him as a “Theologian of Terror,” and he once wrote in an Arabic newspaper editorial that Jews are "the Rapists of worshippers of Allah."

    — Tariq Mehanna and Ahmed Abousamra were mosque members who, in 2009, were indicted by federal prosecutors for providing material support to terrorists and conspiracy to kill in a foreign country.

    Hale cited a sermon delivered by Sheikh Yasir Qadhi, in which he called Christians “spiritually filthy” and said that Muslims could not be citizens of a county where man makes law because they must follow God’s law, as examples of the mosque's misguided teachings.

    “It’s very possible that he [Tamerlan] was influenced by the teachings there,” said Clare Lopez, a senior fellow at The Clarion Project and a strategic policy and intelligence expert with a focus on the Middle East. “We don’t know for certain, but if you look at the way this mosque was founded and who it was founded by, you can at least suspect that he was influenced.”

    Friends and family say that after Tamerlan Tsarnaev's Islamic faith had taken a sharp turn toward extremism sometime around 2009, the year he quit smoking, drinking and boxing. They say he also had begun to influence the religious beliefs of his younger brother, Dzhokhar Tsarnaev. Their growing faith might have been the cause of an upheaval in the Tsarnaev household, according to a recent report in The Wall Street Journal.

    Officials at the ISB have emphatically disavowed the acts of the brothers, who they characterized as “infrequent” visitors.

    "In their visits, they never exhibited any violent sentiments or behavior," the Islamic Society of Boston said in a statement. "Otherwise, they would have been immediately reported to the FBI. After we learned of their identities, we encouraged anyone who knew them in our congregation to immediately report to law enforcement, which has taken place."

    Mosque officials said Tsarnaev was kicked out three months ago after becoming agitated by a sermon in which an imam praised Martin Luther King Jr., who Tsarnaev said was not worthy of such esteem because he was not Muslim.

    Some Boston-area mosques have said they would not officiate a funeral for Tsarnaev. Tsarnaev's aunt in Makachkala, Russia, told NBC that an unspecified mosque where the family worshipped is refusing to hold services for him, but the mosque was not named. ISB officials said handling Tsarnaev's funeral would not go against their teachings.

    "ISB Cambridge did not deny the deceased suspect his rite of burial," mosque officials said in a statement. "It was not asked to provide those services. If it was, it would offer them to him as it is a community obligation to bury the dead. While we denounce the acts he's accused of, his soul stand before God. Our hearts and prayers are with the victims of this horrible tragedy and their families."

    Tamerlan Tsarnaev was killed after a shootout with police last week. Dzhokhar Tsarnaev is in a hospital recovering from wounds and has reportedly confessed, saying their faith and America’s wars in Afghanistan and Iraq prompted the brothers to set bombs at the finish line of the Boston Marathon, killing three and injuring nearly 200.