On Wednesday night, at the height of the terror alert, New York City police released surveillance video showing a man with a handgun at the scene of a fatal shooting.
It was only one of several videos released in the weeks since the attack that have been widely discussed in the wake of the attacks.
The NYPD has said it was “notifying the public of a possible domestic terrorist incident.”
But what we do know is that, on Wednesday, the man was identified as 27-year-old Ibrahim al-Banna, a U.S. citizen of Libyan descent.
It is unclear if the FBI has charged him with a crime.
The Associated Press first reported that the man had been arrested on Tuesday and that he was expected to be arraigned on Thursday.
It also reported that his girlfriend, who had been with him in the apartment where the attack took place, told investigators that he had threatened her.
At least one other man was also arrested, police said.
The suspect was a resident of a Harlem apartment complex, police spokeswoman Elise Armacost told ABC News.
There were no immediate reports of injuries or deaths in the attack, which occurred around 8:30 p.m.
ET at the end of a three-hour lockdown at the New York Stock Exchange.
The Wall Street Journal reported that witnesses said the suspect and a friend of his had yelled at people, telling them to leave their apartments.
Al-Bana, a resident in the building, told police he was “a little confused” when the two men approached him, Armacust said.
He said the man said something about being a Muslim, and he then told the friend to leave.
The two men then entered the building and “started screaming at the people in the hallways,” Armacosaid.
“They were saying they were going to kill the guy.
He tried to get up, but they were grabbing him,” Armaccost said.
“One of the guys came out of the bathroom, grabbed him by the arm, pulled him to the ground and then they were just going at it.
The person in the hallway was screaming, ‘Get the hell out of here.'”
According to a police statement, the suspects were carrying knives and a gun.
They were not wearing masks.
The suspects left in a vehicle and al-Abanna was apprehended in the parking lot of the Nassau County Building, about a block away from the exchange.
Police did not specify if the vehicle was a car or a truck.
A man was shot in the abdomen and was taken to St. Barnabas Hospital, where he is expected to survive, according to the New Jersey State Police.
The police statement said that a suspect identified as Abu Qatada, a Jordanian citizen, and a woman named Fatima, also from Jordan, were arrested in New Jersey.
Qatza was detained after the attack and later identified by the FBI as the driver of the truck.
He has not been charged with a criminal offense.
NYPD Commissioner William Bratton said that it is “a sad day for the NYPD, the entire New York Police Department and all New Yorkers.”
“We are in the midst of a very, very challenging time, as a nation, with terrorism, and I hope this is the start of a better day,” Bratton told reporters at the White House.
“But, as I said, we will be vigilant, we are going to be vigilant.”
The NYPD also said it has arrested more than 20 people for various offenses related to the attack.
“We’re very, quite worried about what happened tonight,” Branson said.
But he also said that “there is a new level of terrorism that we haven’t seen in a long time, and we’re just going to continue to do everything we can to stop it.”
The Associated News’ Tom Llamas contributed to this report.