FLINT, Mich. A Canadian man was charged on Wednesday with stabbing a Michigan airport police officer in an attack federal investigators are probing as an act of terrorism, according to an indictment filed with the federal court in Flint.

Amor Ftouhi, 49, of Montreal, was previously charged with stabbing officer Jeff Neville at the Bishop International Airport in Flint on June 21. Neville survived the attack.

Ftouhi has been held in detention at an unspecified location since his arrest.

On Wednesday, he was indicted on charges of committing an act of violence at an international airport and interference with airport security, acting U.S. Attorney Daniel Lemisch said in a statement. The charges carry a maximum penalty of up to life in prison.

Ftouhi will be arraigned in federal court in Flint on Wednesday afternoon.

Ftouhi is originally from Tunisia and holds dual Tunisian-Canadian citizenship. He appeared last week before U.S. Magistrate Judge Stephanie Dawkins Davis at the federal courthouse in Flint.

Ftouhi’s attorney, Joan Morgan, said at the time that her client was not seeking bond because of an immigration hold that would bar Ftouhi from leaving jail.

Ftouhi legally entered the United States at Lake Champlain, New York, on June 16 before making his way to Flint, the Federal Bureau of Investigation said. Officials said Ftouhi targeted a city with an international airport, but declined to say why Flint was chosen.

Ftouhi, who was not on the radar of U.S. or Canadian authorities before the attack, was in Michigan as early as June 18, the FBI said. U.S. and Canadian investigators are probing his travel before the attack.

According to the criminal complaint, Ftouhi yelled in Arabic “Allahu akbar” (“God is greatest”) before stabbing Neville.

He also said something to the effect of “You have killed people in Syria, Iraq and Afghanistan, and we are all going to die,” the complaint said.

Ftouhi attempted to buy a gun before the attack, but was unable to do so, the FBI said.

FBI officials declined to provide details on what type of gun Ftouhi attempted to purchase and where. The 12-inch (30.5 cm), serrated knife he used in the attack was bought in the United States.

(Writing by Ben Klayman; Editing by Matthew Lewis)