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The suspect in Saturday's deadly rampage purchased a firearm legally after passing an FBI background check, the company's vice president of hunting operations told FoxNews.com on Sunday.

Jared Lee Loughner, a 22-year-old man with a troubled past who law enforcement say may have been influenced by American Renaissance, a pro-white publication, bought the gun from Sportsman's Warehouse's Tucson store in November.

Loughner, accused of killing six people, shooting Arizona Democratic Rep. Gabrielle Giffords and wounding 13 others, did not present a concealed weapons permit so he was required to pass an FBI background check. He did so"immediately and without incident," said Matt French, speaking from the Sportsman's Warehouse's Utah headquarters.

"To my knowledge, the firearm purchase was without incident," French said.

French could not confirm whether the gun purchased in November was the same gun allegedly used in Saturday's mass shooting, for which Loughner so far has been charged with five counts  of murder and attempted murder. However, he said it was the only recent firearm purchase made by the suspect at their stores.

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"Sportsman's Warehouse is cooperating fully with the authorities in investigating this horrible tragedy," he said. "Our sincere condolences go to those affected by this unspeakable incident."

New details are emerging about Loughner as a law enforcement memo based on information provided by the Department of Homeland Security and obtained by Fox News suggests he may have ties to the American Renaissance group, though it's unclear if he was directly affiliated with the publication or group.

The Southern Poverty Law Center describes the group as "white nationalist" whose leader, Jared Taylor, is "a kind of modern-day version of the refined but racist colonialist of old."

The memo states that there is "no direct connection" between Loughner and the group, "but strong suspicion is being directed at AmRen / American Renaissance. Suspect is possibly linked to this group. (through videos posted on his MySpace and YouTube account.). The group's ideology is anti-government, anti-immigration, anti-ZOG (Zionist Occupational Government), anti-Semitic."

The memo also includes information about the suspect's mother, who works for the Pima County Board of Supervisors and notes that Loughner has multiple arrests but no criminal record.

But Taylor, a 1973 graduate in philosophy from Yale University, told Fox News on Sunday that he had never heard of Loughner until Saturday and has checked the group's records going back 20 years and has not found any subscriptions for Loughner to American Renaissance publications.

He added he has no indication that Loughner ever attended any of the group's events, which have been held on the East Coast where the organization is based.

Taylor also denied references to the group as being "anti-ZOG."

"That is complete nonsense," he said. "I have absolutely no idea what DHS is talking about. We have never used the term 'ZOG.' We have never thought in those terms. If this is the level of research we are getting from DHS, then heaven help us," he said.

Loughner lives with his parents in a Tucson neighborhood that one neighbor described as part of an area that is notorious for "stash houses" for Mexican gangs to bring drugs into the U.S. and store them.

The neighbor, who asked only to be identified as Jon, said he volunteered at a phone bank for Giffords' 2008 congressional campaign. He said none of the neighbors seem to know any member of the Loughner household, which on Sunday was cordoned off. Two run-down jalopies outside the house along with a front walkway littered with empty paint buckets and a garden hose blocked the walkway and door while the entire front yard is covered in a tangled cactus tree.

Nothing like this has ever happened in this neighborhood. "We've had a number of good DEA busts," Jon said. "It's a shock, it really is. ... It's sad, it's been a sad day."

Another neighbor directly across from the home also did not want to give his name, but said a mother, son and father live at the house.

"They weren't real friendly," said the neighbor who described himself as 60 and retired. They mostly didn't talk to anyone and mainly stayed inside. "Loners," he called them.

Another neighbor, Anthony Woods, who was three years behind Loughner in school, said the father in the household was argumentative.

Woods said the dad would complain about everything from neighbors' trash cans on the street to standing too close to his property by the fence. Woods said law enforcement interviewed the mother and father at the Loughner house Saturday night.

"They confiscated a lot of things" from the house, he said.

Pima County Sheriff Clarence Dupnik said Saturday that Loughner had "a troubled past."

"I'm not a psychiatrist so I have no reason to believe the person was insane. Was he unstable? I would agree with that," he said.

Loughner was kicked out of Pima Community College following a series of run-ins with school officials and police at the colleges where he frequently caused disruptions in classrooms and elsewhere on campus, according to The Arizona Republic.

The tensions with school officials led to Loughner's production of a YouTube video in which he declared the college illegal, the newspaper reports.

The college said Loughner could only return if he received mental-health clearance, according to The Arizona Republic.

Loughner is suspected of posting a series of YouTube videos that show a focus on literacy and currency -- as well as his distrust in the government.

"Hello, my name is Jared Lee Loughner," one of the videos says, in words appearing on the screen. "This video is my introduction to you! My favorite activity is conscience dreaming; the greatest inspiration for my political business information. Some of you don't dream -- sadly."

The video, posted Dec. 15, later turns more political.

"The majority of citizens in the United States of America have never read the United States of America's Constitution. You don't have to accept the federalist laws," the video's titles say. "In conclusion, reading the second United States Constitution, I can't trust the current government because of the ratifications: the government is implying mind control and brainwash on the people by controlling grammar. No! I won't pay debt with a currency that's not backed by gold and silver! No! I won't trust in god!"

Loughner's last writing on his MySpace page was just hours before the shooting.

"Goodbye friends," he wrote. "Please don't be mad at me."

Loughner was rejected from enlistment in the U.S. Army because he failed the Army urinalysis, a military official told Fox News.

Records obtained from the Pima County, Ariz., criminal database also show Loughner was arrested in 2007 for possessing drug paraphernalia, a misdemeanor charge. The records suggest that Loughner paid a $20 fee and completed a court-ordered program for drug offenders.

Three months later he was cited for running a stop sign, according to court documents.

Another record shows a 2008 arrest for what’s described as a "local charge" in Marana, Ariz., 20 miles northwest of Tucson. The non-criminal charge was dismissed.

FBI Director Robert Mueller said that the gun used in Saturday's massacre was a Glock semi-automatic 9-mm. gun with extended magazine.

Fox News.com's Judson Berger and Fox News' Jennifer Griffin and James Rosen contributed to this report.