ISIS Calls Ohio State University Attacker a ‘Soldier’

COLUMBUS, Ohio — The Islamic State claimed responsibility on Tuesday for the attack at Ohio State University, calling the student who drove his car into pedestrians and then slashed people with a butcher knife a “soldier” of the terrorist group.

A day after the assault injured 11 people, local and federal law enforcement agencies were searching for evidence to determine whether it was an act of terrorism and whether the assailant acted alone, while the large Somali immigrant community here denounced the attack and braced for a possible backlash.

The attacker, identified as Abdul Razak Ali Artan, a Somali-born Ohio State student, was shot and killed by a police officer.

The Islamic State, which has urged Muslims to carry out attacks in the West, released a one-paragraph statement on its news wire, via the messaging app Telegram, that included the same stock phrases it has used in previous claims. Although there was no immediate evidence that Mr. Artan had declared allegiance to any terrorist group or claimed allegiance to one, the vast majority of attacks claimed this way by the Islamic State have eventually been shown to at least have been inspired by the group’s propaganda.

In the same post, he wrote, “Every single Muslim who disapproves of my actions is a sleeper cell, waiting for a signal. I am warning you Oh America.”

Mr. Artan was admitted to the United States in 2014 as the child of a refugee, his mother, and before that he lived for seven years in Pakistan, federal law enforcement officials said. Catholic Charities of Dallas said Tuesday that investigators had contacted the group because it had supplied “shelter, clothing and other basic humanitarian services for a short time in 2014” to a person who might have been a family member of the attacker.

In Columbus, Mr. Artan lived with his mother, several siblings and possibly other family members crowded into a townhouse apartment in the southwest part of the city. Leaders of local mosques and Somali community groups said they did not know him or his family. On Tuesday, the police and federal agents could be seen entering and leaving the apartment, and questioning other residents of the complex.

“They just seemed like a normal family,” said Joe Brickner, a neighbor. “They always parked right here, that’s the only thing weird about them,” he said, pointing to a fire hydrant, “like they didn’t understand no rules.”

Mr. Artan, who was in his first semester studying management at Ohio State, earned an associate degree with honors this year at Columbus State Community College. Ohio State said he was 18, but investigators say there are conflicting records, and he might have been older. The university police said they had never encountered Mr. Artan before Monday, and local court records show no cases involving him.

In August, he was featured in The Lantern, a campus publication, saying that he had not found a place for a Muslim to pray at Ohio State, and that he was afraid of how people would react if he prayed in the open “with everything that’s going on in the media.” He voiced a similar concern at Columbus State, a fellow student recalled.

“He didn’t talk a lot, but when he did, it was about his beliefs,” and was at times “a little preachy,” said Myranda Thompson, a Columbus State student who was Mr. Artan’s partner for a project in a sociology class. “You could tell he had a passion for his religion. I remember him being upset having to pray around here in the cafeteria,” and a concern about how others would see it.

Even so, “He was always smiling and seemed happy,” and she had no sense that he might snap, she said. “Going to a bigger college like O.S.U., there were more people to pick on him; he may have had a breaking point.”

Other Somalis and Muslims said this week that Mr. Artan’s complaints about a place to pray, or an adverse reaction, rang hollow.

“It’s a nonsense excuse,” said Mahamud Kassin, a math teacher in Columbus who graduated from Ohio State in 2014. “Every library has a place you can worship.”

Jibril Mohamed, a lecturer in Somali language and culture at Ohio State, and adviser to the Somali Students Association, said he had never encountered Mr. Artan, but he spoke with a student who was taking an accounting class with him.

“He said he was a quiet, intelligent young man, he was the kind of guy who knows his content before class, he asks the right questions,” he said. “All of a sudden for him to attack people and lose his life, it makes no sense.”

Over three decades, millions of people have fled Somalia, a country racked by civil wars and terrorism. The Columbus area has the second-largest Somali population in the United States, after the Minneapolis-St. Paul area, estimated by the Somali Community Association of Ohio at 38,000 people.

“We have not had any serious incidents up until now, so this is frightening,” Mr. Mohamed said. “Many of the young Somali people on campus are really scared.”

Nabeel Alauddin, a president of the university’s Muslim Students’ Association, said the attack worried him “because it is getting to be increasingly challenging to be an American Muslim.”

But as a Buckeye, he said, he was angry because “this really was an attack on student safety.”

On Tuesday afternoon, three victims remained hospitalized, and one who was released recounted the attack at a news conference. William Clark, an emeritus professor of materials science and engineering, said he was among several people standing outside Watts Hall, which had been evacuated because of a fire alarm.

They were about to re-enter the building, when “I suddenly heard a shout and then this tremendous crash,” he said, as a silver car drove onto the sidewalk, and slammed into a concrete and brick planter. “It clipped the back of my right leg, and basically flipped me up in the air and I landed on concrete.”

Officials have said that Mr. Artan got out of the car and began slashing people with a butcher knife, and ignored commands by Alan Horujko, a university police officer, to drop the knife. The officer fatally shot him.

“I never heard the assailant say anything,” Professor Clark said. The entire episode seemed to last just “15 to 30 seconds,” he said, but he and others, unsure if it was over, went inside and took shelter in a basement laboratory.

He did not realize he had two deep lacerations above his right ankle until a student pointed out that he had left “footprints of blood all the way down the hall.”

The attack put the sprawling campus on lockdown for about an hour and a half, as people barricaded themselves in academic buildings and dorms.

The claim of responsibility “doesn’t prove that there is a connection to the Islamic State, but it increases the probability that there was one,” said Thomas Joscelyn, a senior fellow at the Foundation for Defense of Democracies.

In its propaganda, the Islamic State has stressed that supporters do not need to plan complex attacks, explicitly calling on them to commit violence with cars, knives or whatever else is at hand.

Hours after the attack, Telegram channels run by Islamic State supporters referred to the assailant as “brother” and used an Arabic hashtag that translates to #OhioAttack.

The statement on Amaq, the Islamic State’s news agency, said the attacker had acted “in response to calls to target the citizens of the international coalition.”