Ottawa police have released the driver who was behind the wheel of a double-decker bus that collided with a transit shelter on Friday, killing three people and injuring 23 others.

The OC Transpo driver was arrested following the horrific crash at the city’s busy Westboro Station. The force of the impact tore through the bus’s top deck, with one passenger describing collapsed seats, blood on the floor and no way to escape the wreckage.

The driver was taken to the police station for an interview and released Saturday without conditions, Ottawa Police Chief Charles Bordeleau said.

“It’s important that the public does not read into the fact that she was arrested,” Bordeleau said during a press conference on Saturday.

“I’m not going to go into the details of why we arrested the driver, but the fact remains that there was an arrest done.”

Investigators are still working to identify the victims of the crash, police said.

“We will not be identifying any of the victims at this time,” Sgt. Cameron Graham said.

Officials initially reported that of the three people killed, two passengers were on the bus and a third person was on the platform. That, the police chief added, still needs to be confirmed.

“That was based on initial information,” Bordeleau said at Saturday’s press conference. “Our investigators, part of their process is to determine exactly where those victims were, either on the bus or on that platform. So we have different pieces of information right now, so we’re going to correct that record.”

In a Saturday morning tweet, The Ottawa Hospital issued an update on the status of patients they received. One remains in critical condition while six others are still listed as serious and four have been upgraded to stable.

According to Miles Cassidy, the chief of Ottawa’s paramedic services, many suffered blunt trauma injuries.

‘A LONG, DETAILED AND COMPLEX INVESTIGATION’

At the press conference, Graham said it will be “a long, detailed and complex investigation.”

“We are reviewing all aspects of the collision, including the vehicle, the roadway, weather and the driver’s actions,” he explained.

“Our job is to determine what caused the collision so we can learn from it and prevent such tragedies from occurring again. We will also be examining the factors in relation to any offences that occurred during this collision.”

Speaking to the media on Friday, Bordeleau suggested that the weather -- icy roads and bitter minus-15 cold -- could be a factor in the crash.

Six collision investigators have been assigned to the case, supported by officers from other sections.

Investigators will be making calculations to determine the speed of the vehicle. The bus and its maintenance records will also be inspected.

Brad Muir, a retired sergeant with the Ontario Provincial Police and a collision reconstruction consultant, told CTV News Channel that the process, including retrieving data from the electronics on the route 269 bus, will take “a couple of days.”

He added that investigators will be looking at the road conditions for tire marks and other evidence.

On Saturday, police drones took overhead images of the crash site while officers collected daytime photographs, took measurements and spoke to witnesses. A tow truck eventually arrived at the scene to pull the mangled bus away from the shelter.

‘THERE WAS BLOOD POOLING UNDERNEATH THE SEATS’

The bus was almost at its 90-passenger capacity when the crash occurred, police say. They are appealing to anyone who was on the bus to identify themselves.

One those passengers is Mike Sharp.

“Where I was (at the back of the bus), there was blood pooling underneath the seats just in front of me,” he told CTV Ottawa, describing the immediate aftermath of the crash. “People’s bodies were being pushed up and compressed in the seats.”

He was lucky to walk away unharmed.

“Seats (were) sort of piling up in front of me and heading towards me, and very quickly (I) realized there was really nowhere for me to go,” he recalled. “The bus was full -- it was full of people… There was nowhere to even escape where I was.”

With files from CTV News’ Annie Bergeron-Oliver, CTV Ottawa and The Canadian Press