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MENOMONIE, Wisc. — A somber mood fell upon the hundreds who gathered here Thursday on the campus of the University of Wisconsin-Stout to pay their last respects to a friend they lost too soon.

A Saudi flag stood side by side with a U.S flag as more than 20 of Hussain Saeed Alnahdi's closest friends shared their fondest memories of their "brother" while holding single white candles — honoring a man who "bridged a gap between the Saudi and local community," in the words of Tommy Hutson, a friend.

There are still many unanswered questions in the violent beating of Alnahdi, 24, a Saudi student at the university who died Monday after he was assaulted and left bloodied near Toppers Pizza on a relatively crowded street early Sunday morning.

A vigil is held for Hussain Saeed Alnahdi, the Saudi student at the University of Wisconsin-Stout who was attacked and killed early Sunday in Menomonie, Wisconsin. Safia Samee Ali / NBC News

The bloody assault has shaken this small college town to its core and led some to question whether the place they'd always thought of as safe and welcoming is as secure as they'd once imagined. Authorities said they aren't dismissing the possibility that the attack was a hate crime.

Police say it's likely that several people saw Alnahdi being beaten as bars closed and students flooded the streets. But other than a witness who allegedly saw a white male about 6 feet tall fleeing on foot, police say they can't confirm any other viable witnesses.

Investigators are reviewing security camera video from nearby establishments to pinpoint the possible assailant and anyone else who might have seen the attack, Menomonie police Cmdr. Todd Swartz told NBC News.

The FBI isn't involved in the investigation, he said.

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Related: Police Look for Leads in Case of Saudi Student Who Died After Assault in Wisconsin

"The first feeling I had was embarrassment for the town" said Mark Pruett, a resident of 26 years and former teacher at the university. "Menomonie is not this kind of place, and I can't imagine this would happen here. We are all still in shock, and our hearts are heavy."

As a suspect remains at large, many of the Saudi students who had embraced their home away from home say they're now apprehensive.

"I'm nervous to walk outside at night knowing he's still not caught," Saud Al-Mazroa, a sophomore from Saudi Arabia, told NBC News. "I don't want my parents and family to know about this, because they are so far away and will be scared for me."

Amber Georgakopoulous, a coffee shop manager who grew up in the area, said: "The visceral reaction is that this is not us. It makes you think, 'Is this who we really are and who we want to be?' And I hope for most of us the answer is no."

Hussain Saeed Alnahdi. Courtesy Tommy Hutson

Alnahdi traveled more than 6,000 miles — leaving behind the desert of his hometown, Buraydah, Saudi Arabia — to make a place in Menomonie, a predominantly white Wisconsin town of fewer than 20,000. He wanted to learn English and study business administration, along with 140 other Saudi students enrolled at the school.

Related: University of Wisconsin-Stout Student From Saudi Arabia Killed

The students made connections with their American classmates and became a family of sorts.

"The last time I saw him, a week before Halloween, he came into the bar, and we spent the whole night talking, and he looked over at the guys [his roommates] and said, 'I love them,'" said Ellen St. George, a friend of Alnahdi's who was also his former English as a Second Language teacher.

"And I'll always remember that because we love him, too," she said.

A makeshift memorial to Hussain Saeed Alnahdi grows outside Toppers Pizza in Menomonie, Wisconsin. Safia Samee Ali / NBC News

Saudi students felt so comfortable at the university that they told their families and friends back home, giving the town a reputation as a safe and welcoming place.

So for years, a small but steady stream of Saudi students made their way across the ocean to this small Midwestern town. All chose to enroll purely because of "word of mouth," said Michel Lee, the university's international affairs adviser, but now "there is concern" that might change.

There are 59,974 college students from Saudi Arabia in the United States, according to the Institute of International Education. They are students like Alnahdi. And the attack has left many, including Saudi officials, unsettled.

Hussain Saeed Alnahdi. University of Wisconsin-Stout

The Saudi consulate in Houston told NBC News that it dispatched a staff lawyer to Menomonie to help look into the case.

"We are in the process of appointing an attorney to help locate the attacker and to request the maximum punishment," the consulate said in a statement. "We trust the authorities will find the offender, and we trust the American courts will ensure a just punishment."

The State Department told NBC News that officials are in contact with the Saudi Embassy and "take very seriously any report of violence against foreign students at U.S. universities."

The attack, some students say, has also exposed an undercurrent of unease in a political climate that has become toxic.

"There is a tension since the election, and people on campus feel it," St. George said.

"Nothing is subtle anymore. It's all out there," she said. "People think they can just put all their hate out there. This is not OK, and I hope it makes people reflect on what they think about other races and religions."