Bicycles and debris lay on a bike path after a motorist drove onto the path near the World Trade Center memorial, striking and killing several people. Picture: Craig Ruttle/AP

New York — The screams seemed too vivid from the start, too visceral to belong to crowds celebrating a crisp and sunny Halloween in Lower Manhattan. The tragedy had unfolded in just minutes, and for hours it remained too senseless to believe.

Police tape surrounded the white pickup truck that a 29-year-old assailant had transformed into an instrument of terror when he began hitting cyclists and joggers along the West Side Highway bike path. A mangled school bus sat next to it.

Bodies lay strewn along the way. For those who encountered the scene Tuesday, the aftermath was as confusing as it was gruesome.

Tom Kendrick, 36, a lawyer from the West Village neighborhood, said he was jogging uptown just north of Chambers Street when he began noticing the mayhem on the bike path. He saw a battered body and bicycle in the bushes alongside the path. Farther along he found three bodies close together, also battered cyclists.

“I approached to see if I could help, and they did not need help — they appeared to be dead,” said Kendrick.

“They were bloody and unconscious, with some limbs hanging,” he said. “It was gruesome. It was grisly. It was surreal.”

“These people were gone,” he said. “I’m in shock. I’m looking at dead bodies.”

At least eight people lost their lives in what was the deadliest terrorist attack to strike New York City since Sept. 11, 2001, and about a dozen more were injured.

Hiro Kimura, 15, a sophomore at Stuyvesant High School, said that he and his friends heard “a big car crash.” Then they heard shooting.

“We saw flocks of children running” from the scene, Hiro said.

The New York City police commissioner, James P. O’Neill, gave a preliminary timeline of the violence, which he called an “act of terror,” in a news conference Tuesday evening.

The white truck entered the bicycle path alongside West Street by Houston Street at 3:05 p.m. and headed south, hitting pedestrians and cyclists along the way. The truck, labelled with Home Depot logos, went 20 blocks before ramming into a school bus at Chambers Street. Two adults and two children who were on the bus were reportedly injured in the crash.

The 29-year-old man driving the truck exited the vehicle with what appeared to be two handguns, O’Neill said, at which point a uniformed officer approached the man and shot him in the abdomen. Early reports suggested that the assailant may have yelled “Allahu akbar,” Arabic for “God is great,” after exiting his vehicle. A paintball gun and a pellet gun were recovered from the scene later.

Many of the children attending schools in the area were horror-struck.

The mother of a 13-year-old girl who came face-to-face with the suspect said her daughter was “too traumatised” to talk. The woman, her daughter and two other children were being escorted from the scene by a police officer. She did not want to give her name or her child’s name for security reasons, she said. The girl’s face was red and tear-streaked, and she curled her hands into the sleeves of her blue hooded sweatshirt. Her mother said she was a student at Intermediate School 289 on Warren Street, yards from where the truck came to a rest after crashing into the school bus.

“She was right in front of the shooter,” the woman said of her daughter. “He had two guns.” She said she did not remember much else.

Olivia Raykhman, 14, glimpsed the wrecked school bus in the immediate aftermath of the episode. “They were sawing through a school bus window. They broke all of the windows and were trying to pull kids out. There was a man covering a child with a blanket. There was one kid who was stuck,” she said.

“We ran into the building, and they told us to hide,” said Olivia, a freshman.

She took shelter in what she called a “cellar” with a group that was at first just 15 people. Around 50 more soon joined.

As Olivia and her friends ran inside, students on the upper floors of Stuyvesant recorded video of what was happening on the street. Videos posted on Facebook and circulated over Snapchat showed what appeared to be the suspect, a bearded man in dark clothing, heading down the street with his weapons in his hands, next to a white pickup truck.

Adria Menezes, 45, said she saw the suspect firing one of his weapons at cars on West Street.

Menezes had just arrived at Public School 89, which shares space with I.S. 289, at 3:03 p.m. to pick up two children she baby-sits when she suddenly heard cars crashing on West Street and saw a yellow school bus “drive like crazy.”

Then, roughly 15 feet away, she saw a tall man with dark hair and a hat. He was walking quickly, screaming something indiscernible and shooting at the cars, causing further mayhem.

“When I saw the man shooting at all the cars, we threw ourselves to the ground,” she said in Spanish by phone from inside the school, which remained locked down.

Marie Hui was visiting New York City with several friends from Vancouver, British Columbia, and had been in the SoHo neighborhood shopping before the attack. Several of her friends were at the Sept. 11 Memorial and sheltered in place.

“We’re from Vancouver,” she said. “This doesn’t happen over there.”

The New York Times