WASHINGTON — Hate crimes against Muslim Americans and mosques across the United States have tripled in the wake of the terrorist attacks in Paris and San Bernardino, Calif., with dozens occurring within just a month, according to new data.
The spike includes assaults on hijab-wearing students; arsons and vandalism at mosques; and shootings and death threats at Islamic-owned businesses, an analysis by a California State University research group has found.
President Obama and civil rights leaders have warned about anecdotal evidence of a recent Muslim backlash, particularly in California. But the analysis is the first to document the rise, amid a crescendo of anti-Islamic statements from politicians.
“The terrorist attacks, coupled with the ubiquity of these anti-Muslim stereotypes seeping into the mainstream, have emboldened people to act upon this fear and anger,” said Brian Levin, a criminologist at California State University, San Bernardino.
Mr. Levin runs a hate-crimes research group at the university, the Center for the Study of Hate and Extremism, which produced the analysis and provided the results to The New York Times.
In recent years, there has been an average of 12.6 suspected hate crimes against Muslims in the United States a month, based on F.B.I. data analyzed by the research group.
But the rate of attacks has tripled since the attacks in Paris on Nov. 13 by Islamic State operatives, with 38 attacks regarded as anti-Islamic in nature, according to the analysis, which was based on reports from the news media and civil rights groups.
Eighteen of the episodes have come since the shooting in San Bernardino on Dec. 2 by a Muslim couple who were supporters of the Islamic State, also known as ISIS or ISIL, which left 14 people dead.
The frequency of the recent attacks has not reached the levels seen in the immediate aftermath of the terrorist attacks of Sept. 11, 2001, when there were hundreds of attacks on Muslims, and some Sikhs mistaken for Muslims, but Mr. Levin said they were similar types of hate-crime attacks.
“I’m saddened by this but not surprised,” he said. “Whenever we see intergroup conflicts making headlines, we often see a spike in hate crime accompanying it.”
A week after the Paris attacks, a sixth-grade girl in the Bronx was reportedly attacked by three boys who tried to take off the hijab she was wearing, punched her and called her “ISIS.”
Days later, a college student in a parking lot in San Diego reported a similar assault, with her attacker yelling anti-Muslim slurs.
In Pittsburgh, a passenger in a cab shot the driver, who was Muslim, in the back after the passenger angrily asked him about ISIS and mocked the Prophet Muhammad, the authorities said. And in Anaheim, Calif., a bullet-riddled copy of the Quran was left outside an Islamic clothing store.
The most recent episode cataloged by the San Bernardino research group came Tuesday, when a man reportedly pulled a knife on a Muslim woman at a carwash and threatened her. He was arrested, as the attackers have been in a number of other cases, but many of the episodes remain under investigation by federal and local authorities.
“We are always monitoring that kind of situation,” Attorney General Loretta E. Lynch told reporters last month. “We are always on the lookout for backlash against any individuals for any reason — real or perceived.”
Ibrahim Hooper, a spokesman for the Council on American-Islamic Relations, said the tripling of hate crimes identified by the San Bernardino researchers corroborated anecdotal evidence his group had collected.
“We’re seeing so many of these things happening that it’s unbelievable,” he said in an interview. “It’s off the chart, and I don’t think we’ve seen the end of it.”