Experts on Islam and terrorism are decrying the Department of Homeland Security’s recently revealed anti-terrorism training guidelines, which pressure cops to ignore Islamic beliefs when investigating terror crimes.

The Boston bombings demonstrated the impact of such training, Andrew McCarthy, a former New York prosecutor, told The Daily Caller.

“The Boston Marathon was bombed by a jihadist who had been investigated by the FBI … [and was confirmed in 2011 to be] an Islamist, which would have been hard not to do since he does not appear to have made any secret of it,” said McCarthy, who persuaded a New York jury in 1995 to convict “Blind Sheikh” Omar Abdel-Rahman for his use of Islamic teaching to spur jihad attacks, including the 1993 attack against the Twin Towers.

But before the bombing, “the FBI closed its file [on Tamerlan Tsarnaev] because it found this did not constitute ‘derogatory information,’” McCarthy said.

McCarthy and other security experts, and even members of the American Islamic community, indicate that a culture of excessive concern for the sensibilities of Muslims supremacists is preventing law enforcement agencies from pursuing jihadists.

The 2011 guidelines unveiled Thursday by The Daily Caller are part of this pattern of deferring to Islamist chauvinism. (Related: Homeland Security guidelines advise deference to pro-Shariah Muslim supremacists)

Under the federal guidelines, “agents are admonished to discount the possibility that an Islamist’s constitutionally protected abhorrence of the United States might possibly lead to violence,” McCarthy told TheDC.

Even if FBI officials had learned about Tsarnaev’s 2012 trip to a part of southern Russia that is embroiled in a jihadi war, they would not have restarted their 2011 investigation, a government official told the Washington Post in April.

“The FBI investigation into the individual in question had been closed six months prior to his departure from the United States and more than a year before his return. …Since there was no derogatory information, there was no reason to suggest that additional action was warranted,” the official said in April.

On his six-month trip, starting in January 2012, Tsarnaev visited several militant Islamic leaders and mosques in Dagestan, where jihadis are fighting the Russian government, according to several U.S. and Russian media sources.

“The fiasco regarding Boston is a prime example” of how bad training degrades security, said Robert Spencer, an authority on Islamic doctrine who is heavily criticized by Islamic groups in the United States. He noted that even though FBI agents had interviewed Tamerlan Tsarnaev, the FBI was unable to identify Tsarnaev in crowd photographs taken before and after the bomb strike.

After the attack, FBI officials also did not ask the main mosque in Boston for help in identifying the suspects, said Nichole Mossalam, a spokeswoman for the Islamic Society of Boston.

“We were the ones who reached out to them … on Friday” once the picture were released, Mossalam told TheDC.

Under the federal guideline, the FBI officials had “no reason to go to the mosque since the [Tsarnaev] brothers don’t show any outward signs in the [street] photos of being Muslims,” said McCarthy.

Because of the guidelines, it would be “a ‘profiling’ scandal to show the pictures at the mosque just because it was a bombing with … no other evidence of connection to Muslims,” he said.

The guidelines, titled “Countering Violent Extremism (CVE) Training Do’s and Don’ts,” don’t merely promote respect for free expression but actively promote extremist views by telling officials to sideline experts who “venture too deep into the weeds of [Islamic] religious doctrines and history. … [T]hese topics are not necessary in order to understand the [Muslim] community.”

The DHS also actively discourages engagement with moderate Muslims. “Don’t use trainers … who are self-professed ‘Muslim reformers’ … [or who] equate radical thought [or] religious expressions … with criminal activity,” say the training guidelines.

The guidelines also advise cops, “Don’t use a trainer or training that has received repeated external negative feedback … don’t use training that treats the American Muslim community as a problem rather than as a partner … don’t use training that relies on fear [for example, by citing convictions that show] mainstream Muslim organizations have terrorist ties.”

The training guidelines go so far as to urge federal officials to rely on a political report by the Muslim Public Affairs Committee (MPAC), a Los Angeles, California-based Islamic advocacy group with extensive ties to jihadists and Islamist groups, including the Egypt-based Muslim Brotherhood.

The group’s spokeswoman, Miriam Baja, declined to comment on the controversy. The group’s leader, Salam Al-Marayati, is on vacation, she said.

TheDC asked whether cops should consider religious observance and dress when considering people’s future behavior. “That doesn’t necessarily mean anything,” Baja replied.

MPAC’s report [pdf], titled “Building Bridges,” downplays Islam’s role in spurring terrorism. “Despite the fact that only 8% of Muslims believe suicide bombing against civilians is ‘often/sometimes’ justified, some biased commentators have voiced doubt over the loyalty of Muslim Americans and argue they constitute a domestic security threat,” the report reads.

Security officials, the report claims, should delegate many anti-terror activities to local Islamist political groups. “This report argues the most effective way to deal with the challenge of radicalization and violent extremism is for law enforcement and Muslim American community leaders to partner together,” the report says.

The report’s recommendations were implemented by an August 2011 White House policy signed by President Barack.

“Communities — especially Muslim American communities whose children, families and neighbors are being targeted for recruitment by al-Qaida — are often best positioned to take the lead because they know their communities best,” said the directive [pdf], titled “Empowering Local Partners to Prevent Violent Extremism in the United States.”

McCarthy called MPAC “an Islamist organization whose founders openly admired the Muslim Brotherhood and Hezbollah, and whose director [Salam al-Marayati] suggested that the state of Israel should be a top suspect in the 9/11 attacks. I don’t find any of that particularly trustworthy.”

Marayati, however, claims he offered his services to law enforcement officials after the Boston Marathon attacks. “I then called the FBI to speak with the counterterrorism chief and asked him if there was any information we could share with our community leaders in Boston and what they should do if they had seen anything suspicious leading up to the bombing,” he wrote in an April 23 article for the Washington Post.

“I asked him if there was anything I could do to help. Like all Americans, I did not know the background of the culprits, and it did not matter. I offered my assistance as my civic duty to the country, no matter what others may think,” he wrote.

The article did not say how the FBI reacted to al-Marayati’s offer, or what he offered.

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