MINNEAPOLIS -- Governor Dayton was quick to call the attack on the Dar Al Farooq Center an act of terrorism, a day after an unknown person tossed a homemade bomb through the window of the lead imam's office at the Bloomington mosque.

But investigators aren't using that label yet because they don't have enough details about the perpetrator's motives.

"It's premature to ever label a crime until you have evidence, and until you identify who the attacker is and why he or she or they did what they did you can't call it anything," Tom Heffelfinger, a veteran federal prosecutor who served two stints as US Attorney for Minnesota, told KARE.

The FBI has referred to the bombing as an "incident" and an "explosion" but hasn't used the term domestic terrorism thus far. But the agency noted the use of a destructive device was enough to warrant the agency's involvement in the case.

"Because it was an act of violence perpetrated against a mosque at the beginning of a prayer session, one could conclude it might be a hate crime. One could also conclude it must be an act of terror," he explained.

"But both of those those crimes require that you know who the perpetrator is and what his or her motivations are."

Heffelfinger noted that the federal criminal code is very specific about what it takes to meet the threshold for those crimes.

"Domestic terrorism" is defined in Title 18, USC 2331, as an act intended "to intimidate or coerce a civilian population" or "to influence the policy of a government by intimidation or coercion" or "affect the conduct of the government by mass destruction, assassination or kidnapping."

A hate crime, as defined by Title 18, USC 249, is an act targeting victims because of perceived race, color, religion or national origin.

"Hate crimes, domestic terrorism, use of weapons of mass destruction -- those are all among the most serious crimes under federal law, and so having a label is not necessary to motivate the FBI or the US Attorney," Heffelfinger remarked.

"They're already well motivated. Labels aren't as important as bringing someone into custody."

Asad Zaman, the executive director of the Muslim American Society of Minnesota, told KARE those who worship at Dar Al Farooq and the larger Twin Cities Muslim community does feel terrorized as a result of the bombing.

And while members of the mosque and Zaman are thankful there were no injuries, he said they're surprised that President Trump did not mention the attack on his Twitter feed.

"The President of this country, who tweets about terror attacks, has not seen fit to tweet about this."