"The evidence points toward acts of hate," Grewal said. "I can confirm that we are investigating this matter as potential acts of domestic terror, fueled both by anti-Semitism and anti-law enforcement beliefs."
Six people, including the man and woman who carried out the attack, three civilians and a police officer died in a series of events that ended in a police shootout on Tuesday in Jersey City, New Jersey, across the Hudson River from New York City.
The four-hour gun battle at the JC Kosher Supermarket erupted after the pair shot the police officer at a nearby cemetery and then fled in a white van. It ended after police crashed an armored vehicle through the wall of the market.
Authorities said they were examining social media posts and other evidence to learn more about the attackers' motives and said that at least one of them appeared to be linked to a group called the Black Hebrew Israelites, a group unaffiliated with mainstream Judaism which the Southern Poverty Law Center lists as a hate group.