Two months before he plunged kitchen knives into 10 shoppers at St. Cloud's Crossroads Center mall, after reportedly asking some if they were Muslim, Dahir Adan shared a radically different message on Twitter.

"Don't ever say that ISIS represents Islam," read part of a post @D_Adan retweeted on July 4, 2016.

That same terrorist group would deem the 20-year-old Adan a "soldier of the Islamic State" hours after he was gunned down by an off-duty police officer inside the mall on Sept. 17, 2016. The FBI, for its part, quickly labeled the case a "potential act of terrorism."

But one year after Adan's rampage, newly unsealed court filings detailing the FBI's early response underline the difficulty that persists in trying to unwrap the young man's motivation and determine whether he had any guidance from virtual terror planners abroad.

Days after sending more than 20 agents to St. Cloud to interview scores of witnesses, the FBI obtained search warrants for Adan's social media accounts, the Toyota Camry he was driving when he struck a bicyclist on his way to the mall and four digital devices, according to court filings. But authorities still say they may never know what sparked Adan's decision to bring two Farberware kitchen knives to the mall that night.

FBI special agent in charge Richard Thornton told reporters last year that the bright young college student may have been radicalized "almost overnight," growing withdrawn and scolding relatives for not being more devout.

Dahir Adan was killed by an off-duty officer at the Crossroads Center mall.

The FBI retrieved data from an Apple account associated with Adan's phone number, according to filings, but agents have not shared the results of any searches of Adan's electronic devices.

Authorities have not found contacts between Adan and operatives of the Islamic State of Iraq and Syria, instead pointing to witness statements that Adan shouted "Allahu akbar," an Arabic phrase meaning "God is great," and that he first asked some victims if they were Muslim before stabbing them.

Thomas Joscelyn, a senior fellow at the Foundation for Defense of Democracies, said the circumstances surrounding ISIS claiming Adan's attack has him wondering: "Is there part of the picture we're still not seeing?" ISIS, meanwhile, did not take credit for a pair of bombings in New York and New Jersey that hurt more than two dozen people the same day as Adan's attack.

"I don't think we can make a sweeping generalization of what they claim and don't claim," Joscelyn said. "More often than not there's some sort of definitive connection, whether it's inspired, guided or some sort of real-world connection."

An official ISIS magazine, Rumiyah, further lionized Adan as "our brother Dahir Adan" in its October 2016 publication, listing only the St. Cloud attack among its U.S. "operations" in an annual roundup of the group's affiliated attacks worldwide. The publication described the stabbing victims as "kuffar," or disbelievers, and published an image of paramedics tending to a victim outside the mall.

The same issue published an article recommending using knives in attacks because of their wide availability. But, perhaps in response to Adan's attack, the group "explicitly advised" against kitchen knives "as their basic structure is not designed to handle the kind of vigorous application used for assassinations and slaughter."

The group also wrote that it was "essential to leave some kind of evidence or insignia identifying the motive and allegiance" to ISIS — either a note pinned to a body or a recorded "final testament if the operation will be of a nature where the expected outcome is one's shahadah," or death.

Messages were left seeking comment from a lawyer for Adan's family.

A family friend who declined to be identified for this story said that one year later, he still "didn't have a clue" as to what happened to Adan.

No 'clear-cut answers'

Minnesotans previously have been linked to attempts at directing terror plots from afar.

Before his arrest in Somalia, Mohamed Abdullahi Hassan, a former Minneapolis high school student who became a prolific online recruiter for Al-Shabab after joining the militant Islamist group in 2009, was in the ear of one of two men killed before they tried to shoot up a Muhammad Art Exhibit and Contest in Texas two years ago. Hassan allegedly traded more than 550 messages with attacker Elton Simpson, from November 2014 up until the day of the May 3, 2015, foiled terror plot.

The opacity of Adan's case has been difficult for St. Cloud, said Natalie Ringsmuth, who directs #UniteCloud, a nonprofit that has worked to ease cultural tensions. Ringsmuth said the stabbing is still referenced by anti-Muslim activists visiting the city, as recently as last week. Meanwhile, she said not knowing whether Adan was indeed radicalized has curbed the opportunity to discuss preventing a similar episode.

"We don't know specifically how to talk about it," she said. "And we find when there are not clear-cut answers or the truth is not available, people just fill in their own truths."

Not 'if,' but 'when'

Terrorism or not, the story of law enforcement's response to Adan's attack has since made the lecture circuit.

"There were people that were terrified," St. Cloud Police Chief William Blair Anderson told a room of law enforcement officials at a retail crime symposium last month. "The average working citizen in that community was terrified. And they needed to see that we had control of this. They needed to see that we weren't scared. They needed to see that we knew the extent of this."

Anderson applauded retailers for capturing footage of the attack on their surveillance systems — something he said the mall itself did not have. Anderson also recognized Jason Falconer, the off-duty officer who shot Adan as he continued to advance on Falconer with the pair of knives. Falconer fired 10 shots, Anderson said, striking Adan six times before he died from his injuries.

The attack inspired a successful bid to the city for additional funds for training, Anderson said, and he recommended that other local law enforcement agencies gird for what he described as a new reality.

"For all of us it's not a matter of if this is going to happen," Anderson said. "Now, in the time in which we live, it's when. When is it going to happen?"

Stephen Montemayor • 612-673-1755

Twitter: @smontemayor