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Investigators would have been "crucified" over First Amendment rights if they had launched a full-scale probe into e-mails Fort Hood massacre suspect Army Maj. Nidal Malik Hasan allegedly sent to a radical imam, a government investigator told Fox News.

The claim comes as the squabble grows among officials in different branches of law enforcement and the military over who knew what, and when, about Hasan's leanings toward faith-inspired violence, and amid charges that "political correctness" prevented officials from taking pre-emptive action.

Multiple investigators familiar with the FBI's review of the Fort Hood case told Fox News that they simply did not have enough evidence to launch an investigation. Though officials discovered Hasan's e-mails to the imam, one government counterterrorism  investigator said the messages suggested he was seeking "spiritual and religious guidance."

"(Hasan) appeared to be at a moral impasse, a moral dilemma who was reaching out for advice," the investigator said. "Had we launched an investigation of Hasan we'd have been crucified."

The investigator added that the communications were shared with the "appropriate chains," including the Department of Defense. The source suggested Hasan may have had other suspicious contacts, telling Fox News "no one missed anything or connections to nefarious individuals."

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Officials have consistently batted down suggestions that they "sat" on critical information about Hasan. One investigator said Monday that "I don't have any evidence" Hasan was given light treatment because of his religion or fear of a discrimination suit.

But even after the attacks, some have been reluctant to cite religion as a factor, as evidence has mounted that the alleged gunman's Muslim faith was at least a partial factor in the decision to mount the attack.

Chicago Mayor Richard Daley pointed to America's "love" affair with guns as the driving factor behind last week's shooting at Fort Hood, becoming the latest and possibly most prominent figure to show a reluctance to cite religion.

"Every day in society someone's being killed. Unfortunately, America loves guns. We love guns to a point that we see the devastation on a daily basis," Daley, whose city has suffered through a rash of violence, told reporters. "You don't blame a group. You don't blame a society, immigrant community because of actions of one group, one individual -- you cannot say that."

The Brady Campaign to Prevent Gun Violence issued a statement last week saying that legislative measures to increase the availability of guns should be rejected in light of the attack.

"This latest tragedy, at a heavily fortified army base, ought to convince more Americans to reject the argument that the solution to gun violence is to arm more people with more guns in more places," the organization's president, Paul Helmke, said.

The message was aimed specifically at a proposal backed by the gun lobby and Sen. Richard Burr, R-N.C., to protect the right of veterans to own guns. Burr responded by accusing Helmke of exploiting the tragedy.

"It is a shame that this process has gotten to a point where some feel that they can exploit the senseless murder of American soldiers in the quest to secure personal triumph," Burr said.

Witnesses report hearing Hasan yell "Allahu Akbar" -- "God is Great" -- during the rampage. Hasan once gave a presentation justifying homicide bombings, according to a witness. In one presentation, he also urged the military to let Muslim members leave the service to avoid "adverse" effects.

But some pointed to stress as a leading factor.

"We're dealing with a very different kind of war here," Dr. Phil McGraw, a celebrity psychologist, told CNN's Larry King on Thursday night. "And we know that there is a tremendous degree of stress with this war. And I think the military will tell you that it's a new animal and nobody knows exactly what to do with it."

But with "political correctness" cited as a reason why warning signs from Hasan were potentially overlooked by the military in the first place, some see Hasan being treated the same way in the wake of the shooting.

Bernard Goldberg, a former CBS News correspondent, took the media to task for its coverage.

"What's the story line they run with? Religion? Of course not. Can't do that. He's a Muslim," he said Friday on Fox News' "The O'Reilly Factor." "They run with post-traumatic stress syndrome because that gives them a chance to take a shot at a couple of wars they never liked from the get-go."

Privately, top Army officers have acknowledged that the massacre may have been a terrorist act.

In a series of e-mails sent 24 hours after the shootings and obtained by Fox News, one colonel in a two-star command instructed subordinate officers: "Please send a message to our training centers, the (logistics support bases), and the (divisions) advising them of ...(their) responsibility to provide this command a status of their respective anti-terrorism plans."

Publicly, however, the army's chief of staff seemed reluctant to acknowledge what appears to be the dominant factor in Hasan's world view: his turn toward Islamist views as he turned against the wars in Afghanistan and Iraq.

"I think the speculation could potentially heighten backlash against some of our Muslim soldiers," said Army Chief of Staff Gen. George Casey. "And what happened at Fort Hood was a tragedy, but I believe it would be an even greater tragedy if our diversity becomes a casualty here."

Some other commentators took note of Hasan's faith only to suggest that its consideration served  to rile up conservatives.

"I cringe that he's a Muslim," said Evan Thomas of Newsweek. "I mean, because it inflames all the fears. I think he's probably just a nut case. But with that label attached to him, it will get the right wing going and it just -- I mean these things are tragic, but that makes it much worse."

Fox News contributor Monica Crowley called that assessment "incredible."

"I think he's knee-deep in political correctness, as so many people are, including now, as we know, the United States military. Political correctness is turning out to be the death of this country," she said.

Satirical blogger Barry Rubin of "The Rubin Report" wondered if today's New York Times covering the Lincoln assassination would overlook the fact that John Wilkes Booth shouted out a Confederate motto after the shooting and report instead that he "was psychologically unstable...frightened of the Civil War coming to an end and having to face a peacetime actors' surplus."

Fox News' James Rosen and Mike Levine contributed to this report.