The FBI is treating a mass shooting on Sunday at a Milwaukee-area Sikh Temple as a possible act of domestic terrorism, officials announced in a press conference Monday. Wade Michael Page, a 40-year-old Army veteran and suspected white supremacist, is believed to be the gunman and was killed at the scene of the crime.

Domestic terrorism is defined by the U.S. Patriot Act as a dangerous action that is intended to intimidate or coerce a “civilian population,” influence government policy by intimidation or affect a government’s actions by “mass destruction, assassination or kidnapping.” Terrorism can be the work of one isolated individual, or a larger network of criminals.

While authorities haven’t disclosed a possible motive for Page to open fire in a Sikh temple an hour before services began, law enforcement sources and advocacy groups say that Page was a longtime white supremacist who played in a white power band called “End Apathy.” This fact could make his crime different from, for example, the mass shooting in Aurora, Colo., two weeks ago, when a gunman killed 12 people in a movie theater seemingly for no reason at all. Police have also refused to release a motive in the Colorado case, but it’s harder to imagine how that attack could have been intended to influence government policy. However, Page’s alleged crime could have been designed to send a message that the government should exclude nonwhite people from America, or any number of anti-minority messages.

Since the Sept. 11 attacks, Sikhs have sometimes been mistaken for Muslims and have increasingly found themselves the target of anti-Muslim hate crimes in America. It’s possible that Page could have mixed up the temple with a mosque and started his attack as a way to make a political statement against Muslims—another political act that seems to fit the bill of terrorism.

Prabhjot Singh, the co-founder of the Sikh Coalition in New York, told Yahoo News that he thinks it’s too soon to talk about whether the attack should be treated as terrorism or a hate crime.

“How we categorize it is not so important right now,” Singh said. “It’s that the nation comes to heal collectively.”

The coalition was founded when hate crimes against Sikhs escalated after 2001, including the murder of gas station owner Balbir Singh Sodhi in Mesa, Ariz., by Frank Roque. The killer was reportedly out for “revenge” for the 9/11 attacks and wrongly assumed the Sikh man was Muslim.

The discussion around what counts as terrorism has been charged since 9/11, when Muslim-American communities were subjected to surveillance and heightened scrutiny out of fear that more terror attacks were on the way.

Domestic terrorism is actually at a four-decade low, according to Gary LaFree at the University of Maryland’s National Consortium for the Study of Terrorism and Responses to Terrorism. (LaFree doesn’t count plots that were thwarted before they were ever attempted.) Between 1980 and 2001, non-Islamic American extremists carried out about two-thirds of all terrorism in the United States, according to FBI statistics cited by the Council on Foreign Relations. Between 2002 and 2005, that figure jumped to 95 percent. In the 10 years following 2001, only 6 percent of terrorist acts in America have been the work of Islamic extremists.

Even so, some scholars say the common perception is that most homegrown terrorists in America are Muslims adhering to a violent brand of Islamist extremism. People are less likely to understand that violent white supremacism can also be terrorism.

“I think that [white supremacist attacks] should quality as terrorism just as much as an individual who’s a Muslim who abuses that faith to say ‘I want to kill these people to further my political agenda,’” said Sahar Aziz, an associate professor at Texas Wesleyan University School of Law. White supremacy is also a political message, she added.

Aziz says that since the Sept. 11 attacks, the government has shifted to focusing law enforcement resources on Islamic extremism, possibly to the detriment of preventing white supremacist attacks and other dangerous extremists.

“I think one of the issues that had bothered me in the aftermath of the Colorado incident and that has bothered … many Muslim, Sikh, Arab and South Asian civil rights advocates is the ease with which the terrorism label applies to some individuals and some incidents and the assumption that if you have a person who isn’t from certain communities then that label isn’t appropriate,” Dawinder “Dave” Sidhu, a Sikh-American law professor at the University of New Mexico, told Yahoo News.

Sidhu added that he thinks terrorism should be redefined to focus on a perpetrator’s actions, not his or her motivations. Terrorism represents “a disregard for human life and a killing of innocents,” he says, not the rationale of a killer that may be unknowable.