NEW YORK — Federal prosecutors brought terrorism charges Wednesday against the Uzbek immigrant accused in the truck rampage that left eight people dead, saying he carried out the attack in response to the Islamic State group's online calls to action and picked Halloween because he knew more people would be out on the streets.
Even as he lay wounded in the hospital from police gunfire, 29-year-old Sayfullo Saipov asked to display the ISIS flag in his room and said "he felt good about what he had done," prosecutors said in court papers.
Meanwhile, the FBI said a second Uzbek — 32-year-old Mukhammadzoir Kadirov — is wanted for questioning in connection with the bloodshed.
Saipov, accused of driving the rented Home Depot pickup truck that lurched down a bike path near the World Trade Center memorial on Tuesday, was charged with providing material support to a terrorist group and committing violence and destruction of motor vehicles, resulting in death.
The charges can bring the death penalty.
His lawyers did not immediately return a message seeking comment.
Saipov left behind knives and a note, handwritten in Arabic, that included Islamic religious references and said "it will endure" — a phrase that commonly refers to ISIS, FBI agent Amber Tyree said in court papers.
Questioned in his hospital bed, Saipov said he had been inspired by ISIS videos that he watched on his cellphone and began plotting an attack about a year ago, deciding to use a truck about two months ago, Tyree said.
During the last few weeks, Saipov searched the internet for information on Halloween in New York City and for truck rentals, the agent said. Saipov even rented a truck on Oct. 22 to practice making turns, Tyree said.
He even considering displaying ISIS flags on the truck during the attack but decided against it because he did not want to draw the attention, authorities said.
John Miller, deputy New York police commissioner for intelligence, said Saipov "appears to have followed, almost exactly to a T, the instructions that ISIS has put out."
In the past few years, the Islamic State has exhorted followers online to use vehicles, knives or other close-at-hand means of killing people in their home countries. England, France and Germany have all seen deadly vehicle attacks since mid-2016.
A November 2016 issue of the group's online magazine detailed features that an attack truck or van should have, suggested renting such a vehicle and recommended targeting crowded streets and outdoor gatherings, according to the SITE Intelligence Group, a militant-monitoring agency.
Carlos Batista, a neighbor of Saipov's in Paterson, New Jersey, said he had seen the suspect and two friends using the same model of rented truck several times in the past three weeks.
It was not clear whether Saipov had been on authorities' radar. Miller said Saipov had never been the subject of a criminal investigation but appears to have links to people who have been investigated.
In Tuesday's attack, Saipov drove his speeding truck for nearly a mile along a bike path, running down cyclists and pedestrians, then crashed into a school bus, authorities said. He was shot in the abdomen after he jumped out of the vehicle brandishing two air guns, one in each hand, and yelling "God is great!" in Arabic, they said.
In addition to those killed, 12 people were injured.
The aftermath took a political turn Wednesday when President Donald Trump slammed the visa lottery program that Saipov used to come to the U.S. in 2010. Trump called the program "a Chuck Schumer beauty," a reference to the Senate's top Democrat.
The program dates to 1990, when Republican President George H.W. Bush signed it as part of a bipartisan immigration bill. Trump called on Congress to eliminate it, saying, "We have to get much tougher, much smarter and less politically correct."
Schumer, who represents New York, said in a statement that he has always believed that immigration "is good for America," and he accused the president of "politicizing and dividing" the country.
Assailants in a number of other recent extremist attacks around the world were found to have been "lone wolves" — inspired but not actually directed by the Islamic State. In some cases, they never even made contact with the group.
On the morning after the bloodshed, city leaders vowed New York would not be intimidated, and they commended New Yorkers for going ahead with Halloween festivities on Tuesday night.
They also said Sunday's New York City Marathon, with 50,000 participants and some 2 million spectators anticipated, will go on as scheduled.
"We will not be cowed. We will not be thrown off by anything," said Mayor Bill de Blasio.
While the mayor said there have been no credible threats of any additional attacks, police said they were adding more sniper teams, bomb-sniffing dogs, helicopters, sand-truck barricades and other security measures along the marathon route, in the subways and at other sites.
The attack killed five people from Argentina, one from Belgium and two Americans, authorities said. Nine people remained hospitalized in serious or critical condition, with injuries that included lost limbs and wounds to the head, chest and neck.
A roughly two-mile stretch of highway in lower Manhattan was closed for much of the day for the investigation. Authorities also converged on Saipov's New Jersey apartment building and a van in a parking lot at a New Jersey Home Depot.
Runners and cyclists who use the popular bike path were diverted from the crime scene by officers at barricades.
"It's the messed-up world we live in these days," said Dave Hartie, 57, who works in finance and rides his bike along the path every morning. "Part of me is surprised it doesn't happen more often."
The slight, bearded Saipov is a legal, permanent U.S. resident. He lived in Ohio and Florida before moving to New Jersey around June, authorities said.
Birth records show he and his wife had two daughters in Ohio, and a neighbor in New Jersey said they recently had a baby boy.
Saipov was a commercial truck driver in Ohio. More recently, he was an Uber driver.
In Ohio, Saipov was an argumentative young man whose career was falling apart and who was "not happy with his life," said Mirrakhmat Muminov, a fellow truck driver from heavily Muslim Uzbekistan.
Saipov lost his insurance on his truck after his rates shot up because of a few traffic tickets, and companies stopped hiring him, said Muminov, 38, of Stow, Ohio. Muminov said he heard from Saipov's friends that Saipov's truck engine blew a few months ago in New Jersey.
Muminov said Saipov would get into arguments with friends and family, tangling over even small things, such as going to a picnic with the Uzbek community.
"He had the habit of disagreeing with everybody," Muminov said.
He said he and Saipov would sometimes argue about politics and world affairs, including Israel and Palestine. He said Saipov never spoke about ISIS, but he could tell his friend held radical views.