Federal authorities investigating a group of Somali-Americans who left their homes last year to join a terrorist group overseas say they've found some of the missing men — on the popular online networking site Facebook.

For several months the FBI has been investigating at least 20 Somali-American men from the Minneapolis area who traveled to war-torn Somalia, where some of them trained and fought with an Al-Qaeda-linked terrorist group known as al-Shabaab, according to counterterrorism officials.

The FBI investigation is looking into two key questions: Where are the missing men now? And how were they radicalized and recruited inside the Unites States? Facebook could help find the answers.

One law enforcement official told Fox News the FBI is "aware that there were some missing [Somali] community members on Facebook," but the official declined to discuss whether any "investigative activity has or hasn't been carried out." The official also declined to specify how many of the missing men were found to be on Facebook.

Fox News was able to find one Facebook user whose uncommon name matches that of one of the missing men. In a photo posted online, the Facebook user is seated on a sofa, smiling, wearing a dark coat and scarf around his neck, and looking like many ordinary Facebook users. He has only about a dozen "friends" listed, most from London, Lebanon and Egypt, but one of them graduated last year from Edina Senior High School just outside Minneapolis.

A spokesman for Facebook, which has more than 175 million users worldwide, said the social networking site can be helpful to an FBI investigation, providing information from a user's page, email addresses associated with a user, or even the location from which a user last accessed Facebook.

"There's a lot of information that we can provide to law enforcement," said Barry Schnitt, Facebook's Senior Manager for Corporate Communications and Public Policy. But he insisted information can only be provided "after going through the proper legal processes."

Both Schnitt and the law enforcement official said legal issues and First Amendment rights limit the FBI's ability to use Facebook as an investigative tool. In order to acquire information from Facebook, authorities need to obtain a court order, a search warrant or a subpoena, which Schnitt called "a pretty low bar."

"We don't just as a matter of routine monitor what's going on on Facebook," the law enforcement official said. "There has to be a predicate to look at Facebook."

When asked if any court orders or warrants had been issued in the case of the missing Minneapolis men, the official declined to comment. Schnitt similarly declined to say whether the FBI had contacted Facebook in the course of its investigation.

Schnitt did acknowledge, though, that Facebook could be used to "spread dangerous ideas."

"There is a risk of technology helping to spread radicalism," he said. And at a Senate hearing on the case last week, Andrew Liepman, the Deputy Director for Intelligence at the National Counterterrorism Center, told lawmakers, "It's clear that the Somali American youth ... were exposed to Al-Shabaab's extremist ideology here in the United States, both in terms of face-to-face contact with extremist elements and on the Internet, and they tended to reinforce each other."

In fact, some Somali-Americans with ties to people involved in the Minneapolis investigation are using Facebook as a platform to express violent sentiments. In one instance, a user posted as his personal portrait what appears to be a stock photo of a man holding the Koran in one hand and a rocket-propelled grenade launcher — aimed straight ahead — in the other. The man in the photo is wearing what looks like a weapons or explosives belt, and his face is covered with a black wrap, only his eyes peering through.

According to Facebook's "terms of use," a user agrees not to post any photos or send any messages deemed "threatening," "harassing," or "hateful." But it's up to other users to flag any violations, Schnitt said.

He acknowledged that the photo described above appears "a little hostile."

"This seems to be a little more menacing, saying 'Here's my book and if you don't agree with my book I'm going to shoot you.'"

The photo has since been taken down, replaced by the silhouette of a generic male.

At the Senate hearing last week, counterterrorism officials insisted that the Internet alone cannot radicalize someone.

"I would see the Internet often as a tool that helps someone along a path, but not the proximate cause that leads someone to get a ticket to go to Mogadishu," said Philip Mudd, the Associate Executive Director of the FBI's National Security Branch.

And though Schnitt admitted technology like Facebook can help spread radicalism, he said that shouldn't "overshadow all the ways it has helped to stop radicalism."

"The benefits far outweigh the risks, and we are doing all we can to [mitigate] the risks," he said.