During an attack that killed four members of a Muslim family in London, Ont., the driver of a black pickup truck revved its engines and sped towards a curb before striking the victims, one of whom was thrown into the air, an eye witness testified on Wednesday.

Nathaniel Veltman, who has pleaded not guilty, is accused of deliberately hitting five members of the Afzaal family with his truck while they were out for a walk. Prosecutors have alleged his actions amount to an act of terrorism.

Testifying at Veltman's trial, 36-year-old Lindsay Marshall told jurors that she was reading a book on the balcony of her apartment near Hyde Park Road and South Carriage Road on June 6, 2021, when she heard a vehicle revving its engine.

Marshall said she looked up and saw a southbound black pickup truck, which accelerated through an intersection and drove up onto a sidewalk.

She said she looked on as a police vehicle arrived and an officer began trying to resuscitate someone who had just been hit.

Marshall recalled being in a state of shock for about an hour before she went downstairs and approached police to give a statement.

"Other cars were coming on the other side of the street, and they started stopping and I kind of just sat there like I don't really know what I just saw," she said.

“So many emergency personnel came and they started cordoning off the area all around, stopping traffic," she added.

"I was just standing there for about an hour, just like in shock at what I saw and couldn't really believe it."

Veltman, who walked into the courtroom on Wednesday morning looking down at his feet, sat next to his lawyers and stared at a monitor screen and a wall in front of him. He took some notes and exchanged pieces of papers with his lawyers, who he spoke to occasionally.

Later Wednesday, jurors began watching video of Veltman at London's police headquarters shortly after his arrest.

The presentation of the edited video, which was expected to last several hours and stretch into Thursday's session, began with footage of police cruisers arriving at the site and continued with images of the booking area, where Veltman was asked his name, age, employment information, as well as questions related to COVID-19 screening and food allergies.

Salman Afzaal, 46, his 44-year-old wife Madiha Salman, their 15-year-old daughter Yumna and her 74-year-old grandmother, Talat Afzaal, were killed in the London attack. The couple's nine-year-old son was also seriously hurt but survived.

Veltman, 22, has pleaded not guilty to four counts of first-degree murder and one count of attempted murder.

Federal prosecutors are arguing that Veltman was motivated by white nationalist beliefs.

Crown lawyer Sarah Shaikh told jurors in her opening statement Monday that Veltman allegedly planned his attack for three months.

She said Veltman told detectives that his intentions were political, he'd left his home on the day of the attack looking for Muslims to kill and that he'd used a truck to send a message to others that vehicles can be used to attack Muslims.

An agreed statement of facts presented to the jury has said Veltman was driving his truck north on Hyde Park Road in London when he saw the Afzaal family and made a U-turn to drive south towards them. Two women in the Afzaal family were wearing traditional Pakistani clothes at the time of the attack.

Veltman accelerated as he approached the family, and data from his truck show he steered to the right, aiming to hit the family, just five seconds before striking them, the statement said.

"From five seconds before the impact through until point of impact, the brake pedal was never depressed," it said. "Veltman struck the victims with his truck and at least one family member was thrown high in the air."

The jury was shown video on Tuesday of Veltman speeding his truck, seen with a heavily damaged front end, into an almost empty mall parking lot a few minutes after the attack, and stopping next to a parked cab. Court heard he asked the cab driver to call 911 and said he had intentionally struck several people.

The video – extracted and edited from security camera footage from the mall – shows three police vehicles arriving about two minutes later, followed by more police vehicles minutes after that.

Veltman is seen leaving his truck and taking a few steps before kneeling down and putting his hands on his head as officers approach and arrest him.

The trial, which is taking place in Windsor, Ont., is expected to last eight weeks.