NEW YORK (CBSNewYork/AP) — Federal prosecutors announced late Wednesday afternoon that terror charges were filed against the suspected assailant in Tuesday’s attack in Lower Manhattan that left eight people dead.

“Yesterday afternoon, a man consumed by hate and a twisted ideology attacked our country and our city,” said Joon Kim, Acting U.S. Attorney for the Southern District of New York.

But thanks to the diligence of law enforcement and prosecutors, charges were filed 24 hours after the attack, Kim said.

Suspect Sayfullo Saipov was shackled in a wheelchair Wednesday night as he faced a federal judge.

Authorities said Saipov had been planning the attack for a “number of weeks” and did it “in the name of ISIS.”

Saipov left behind knives and a note, in Arabic and English, that included Islamic religious references and said, “Islamic Supplication. It will endure,” FBI agent Amber Tyree said in court papers. “It will endure” commonly refers to ISIS, Tyree said.

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.

“This is the preferred weapon of choice now,” said retired FBI Agent Manny Gomez. “It’s easy to run — to steal, borrow, or use your own vehicle to commit these types of acts.”

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, and he initially hoped to get from the bike path across lower Manhattan to hit more pedestrians on the Brooklyn Bridge, Tyree said.

The complaint against Kim includes two charges – material support of a terrorist organization, specifically ISIS, and a federal charge of violence and destruction of a motor vehicle with willful disregard for human life.

The first charge carries a maximum sentence of life in prison upon conviction, while the second is eligible for the death penalty, Kim said. But Kim noted that only a criminal complaint has been filed, and the counts against Saipov are still subject to a grand jury indictment before other steps leading to a trial.

Read The Criminal Complaint

There had been questions about the legal status of the suspect. The White House had previously said Saipov was considered an enemy combatant and would face military justice. But the charges issued Wednesday place him in the civilian court system — and Kim said the determination about whether he would be made an enemy combatant would be made elsewhere than the U.S. Attorney’s office.

“This was the act of a depraved coward,” said Gov. Andrew Cuomo. “There is no grand statement to what was done. It was the act of a coward.”

Earlier, the FBI had announced they were looking for a second man from Uzbekistan in the attack and thought he might have information on it. But early Wednesday evening, FBI Assistant Director in Charge William F. Sweeney Jr. said the agency was no longer seeking the man.

“We have found him, and we’ll leave it at that,” Sweeney said.

As CBS2’s Tony Aiello reported, investigators late Wednesday were tracing all of suspect Sayfullo’s steps in the days leading up to the attack and looking into his past.

Speaking at a news conference Wednesday, Police Commissioner James O’Neill called it “the worst terror attack in New York City since Sept 11, 2001.”

“What happened yesterday was not OK,” O’Neill said. “It will never be something any of us will just accept as inevitable.”

Meanwhile, under arrest at NYC Health + Hospitals/Bellevue Wednesday Saipov is said to have no remorse. He reportedly told investigators he was “pleased” with the success of the attack.

His pleasure was a source of great pain to those who witnessed the bloodbath on the West Side bike path Tuesday.

As CBS2’s Jessica Layton reported, NYPD officers were guarding the corners at West and Chambers streets late Wednesday, a full day after the Halloween afternoon act of terror.

“All of a sudden I see a white truck – just 60 miles an hour, speeding down the bike trail. And then I hear, ‘Boom! Boom! Boom! Boom!’ and I look up and there are bike pieces in the air; there are body parts flying,” said Borough of Manhattan Community College student Nayali Noboa. “And I froze. What am I supposed to do?”

Noboa said she cannot comprehend the twisted motivation behind the attack. But hundreds of investigators are working 24/7 to do just that.

“We are working hard to get to the bottom of exactly what happened yesterday and why, and working tirelessly to prevent anything like this from getting repeated,” O’Neill said.

NYPD Deputy Commissioner of Intelligence and Counterterrorism John Miller said Saipov left handwritten notes in his rented Home Depot pickup.

Kim said the notes translated to, “No god but god and Mohammed is his prophet, and “Islamic supplication, it will endure” – the latter a phrase commonly used by ISIS.

A search of cellphones Saipov possessed revealed some 3,800 images related to ISIS, as well as about 90 videos, Kim said. The videos depicted, among other things, ISIS fighters killing prisoners by running them over with a tank, beheading them, and shooting them in the face, Kim said.

“He appears to have followed, almost exactly to a ‘T,’ the instructions that ISIS has put out in its social media channels before with instructions to their followers on how to carry out such an attack,” Miller said.

Sources tell CBS News that Saipov appears only to have been inspired by ISIS and not specifically directed by the group.

Investigators believe he read and closely followed instructions in an article from an ISIS publication, spelling out how jihadis should use trucks to commit terror attacks.

Saipov also admitted that he rented a truck on Sunday, Oct. 22, to practice the turns he would make in his attack nine days later, Kim said.

Meanwhile, CBS News reported that in 2015, Saipov was known to the FBI as an associate of subjects in a terror plot, but he was not the focus or a target of an investigation at the time.

“What we are looking for is: how has he touched the subjects of other investigations, what is his connectivity to those people? And we’re kind of building out in concentric circles to try and document that. But it appears he will have some connectivity to individuals who were the subjects of investigation, though he himself was not,” he said.

The NYPD said Saipov rented the Home Depot truck he used in the attack at 2:06 p.m. Tuesday in Passaic, New Jersey. He drove over the George Washington Bridge, exiting at 2:43 p.m.

At 3:04 p.m., Saipov entered the West Side bike path at Houston Street. He headed south for 14 blocks, targeting pedestrians and bicyclists, police said.

At 3:08 p.m., it was over after Saipov crashed into a school bus at Chambers Street, police said.

Meanwhile, investigators have also tracked Saipov’s recent movements using E-ZPass and license plate reader records. Miller also said Saipov planned the attack for weeks and conducted reconnaissance of the bike path.

Authorities also updated the number of those injured in the attack. FDNY Commissioner Daniel Nigro said in addition to the eight killed, 12 people were hurt, including four who are in critical but stable condition. He said the injuries range from amputations to head and body trauma.

Of those killed in the attack, five were visiting from Argentina, while one was from Belgium.

Police said Nicholas Cleves, 23, of Greenwich Village, and Darren Drake, 32, of New Milford, New Jersey, were also killed.

LOWER MANHATTAN TERROR: Photos | Videos | Road Closures

Authorities said Saipov is a native of the Uzbekistan with ties to Florida and New Jersey.

Speaking on CNN Wednesday morning, Cuomo called the suspect was “associated with ISIS” and “radicalized domestically.”

“Well the evidence shows, and again, it’s only several hours and the investigation is ongoing. But, after he came to the United States is when he started to become informed about ISIS and radical Islamic tactics,” Cuomo said. “We have no evidence yet of associations or a continuing plot or associated plots and our only evidence to date is that this was an isolated incident that he himself performed.”

The governor also ordered that all flags be flown at half-staff Thursday in honor of the victims.

Investigators say Saipov drove the rental truck onto a bike lane at West Street and West Houston Tuesday, plowing right into the path of cyclists. Eugene Duffy, who had just left work, heard the commotion and raced to see what happened.

“I see gentlemen laying there in the bike path who were run over by this pickup truck,” he said.

“There were three bicycles destroyed in a way I didn’t know bicycles could be destroyed,” another witness said. “One was completely bent in half, twisted off.”

The victims were violently thrown off their bikes as Saipov continued driving before he crashed into the rental truck into a small school bus, injuring two adults and two students.

As Saipov exited the truck, sources say he yelled out, “Allahu Akbar,” Arabic for, “God is great.” Cell phone video shows him running with nearby police quickly on his trail.

One of the officers ordered him to drop his weapons, a pellet and paintball gun, according to police. When he refused, that’s when the officer fired.

“I see two cops, they were ducked behind a car and I heard nine to 10 gunshots,” one witness said.

Saipov was shot in the abdomen by hero NYPD Officer Ryan Nash and was rushed to the hospital. He was in critical condition but expected to survive. Miller said Wednesday that multiple knives were also recovered at the scene.

Investigators tell CBS News Saipov probably intended to use the weapons to harm even more people, but simply could not reach them after he crashed, CBS2’s Janelle Burrell reported.

Both Cuomo and Mayor Bill de Blasio Wednesday commended the officer who shot the suspect, calling him a hero.

“What he did was extraordinary,” the mayor said.

A roughly two-mile stretch of highway in Lower Manhattan is shut down for the investigation. Authorities also converged on a New Jersey home and a van in a parking lot at a New Jersey Home Depot store.

De Blasio said there were no additional or credible threats to New York City.

“We understand this an attack on our values,” he said. “But as an effort to break our spirit, it failed.”

Police and the FBI urged members of the public to give them any photos or video that could help. The attack echoed a strategy that the Islamic State group has been suggesting to its followers.

If you have video or photos of the attack, share it with us. You can help with the investigation. Send to: https://t.co/VvyXNdsME3 or call. pic.twitter.com/u21J6cZ72K — NYPD NEWS (@NYPDnews) November 1, 2017

“ISIS has gotten it down to a simple formula that they have put on the Internet,” Cuomo said. “And it doesn’t take a rocket scientist to rent a car, rent a truck. But, they are cowards and they are depraved. I resist the temptation to delve into who they were, and why, and we know why. They hate America and New York is a target.”

President Donald Trump railed against the Islamic State Tuesday and declared “enough!” and “NOT IN THE U.S.A.!”

Trump announced Wednesday he will ask Congress to “immediately” begin work to terminate the Diversity Immigrant Visa Program, which Homeland Security confirmed was used by the alleged attacker to enter the United States.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)