Police have arrested the suspect on attempted murder charges but say that religion was behind the attack of a 52-year-old Detroit man and his 51-year-old friend who tried to intervene.
Southfield Police Chief Eric Hawkins said 39-year-old Terrence Thomas thought it was unacceptable that the victims were not Muslims.
"The suspect began stabbing one of the victims," Hawkins said of Thomas, of Detroit, who ran from the scene down Greenfield.
Thomas had two knives when police arrested him. He was later charged with attempted murder.
Both victims were treated and released from a nearby hospital.
Federal investigators are getting involved because the attack is believed to be a hate crime.
"It could constitute a hate crime," said Andy Arena, former Detroit FBI chief. "We have to see what really motivated this guy. You call it home-grown radicals, jihadis, this is really the biggest threat throughout the world right now.
"They are on the Internet, social media, they are hearing this message - and they are becoming radicalized."
Police say Thomas was mentally unstable and had drugs on him at the time of his arrest.
"I don't think there should be a litmus test for crazy Muslims," said Dawud Walid, executive director of Council on American Islamic Relations. "Or as if all Muslims are motivated by religion."
Walid's organization CAIR which fights for Islamic rights, said if this incident is ethnic intimidation, Thomas should be charged accordingly. But he does not think Muslims are more vulnerable when it comes to radicalization.
"Anyone who has not health issues on the fringe can be radicalized, be it, either in a street gang or joining something like an international extremist organization," Walid said. "In this case we have to wait and see what the facts are."
Hawkins said police are not ready to leap to any conclusions yet.
"It's important, especially for members of the Southfield community to understand that as far as we know right now, this was an isolated incident," he said.