OTTAWA -- A "beautiful soul," a mother with extended family in the Netherlands and a dad beloved for his sense of humour were the people killed in Ottawa's horrific bus crash last week, the city's police revealed Monday.

All three were public servants in the federal government. The collision injured nearly two dozen more and its cause is still uncertain.

Yet even as the city grieved with the families of those killed and police continued their investigation, the chair of the federal Transportation Safety Board took aim at the federal government for not doing more to increase bus safety.

Bruce Thomlinson, 56, Judy Booth, 57, and Anja Van Beek, 65, were fatally hurt when a double-decker bus slammed into a shelter at a station west of downtown Ottawa at the start of the evening rush hour on Friday. It was on an express route from the city core, beginning a long run without a stop on its way to a western suburb.

Thomlinson worked for the Canada Border Services Agency and Van Beek worked for the federal Treasury Board. Booth had retired from the National Capital Commission but still worked there part-time on contract.

In separate statements, the three families remembered their loved ones.

"Bruce was dedicated to his family and will be missed by his wife and his two boys, and extended family and friends," Thomlinson's family wrote, adding that he "gave us great joy in life through his silliness, sense of humour and love of the outdoors."

"Judy was a cherished wife to Ches and loving mother to both of her girls, Holly and Karen," Booth's family wrote. "She was an absolute treasure and a beautiful soul that will be profoundly missed by her family and many friends."

Van Beek similarly left behind a husband and two daughters as well as family in Ottawa, Toronto and the Netherlands. "As you can understand, her family is grieving and would appreciate if you respected their privacy."

While the families of the three grappled with their loss over the weekend, some federal civil servants only learned what had happened to their co-workers upon returning to work on Monday.

An email sent to CBSA staff Monday morning said one employee there had been killed and one seriously injured, and two other workers had family members hurt in the crash. One employee told The Canadian Press staff members were in tears after learning Thomlinson had been killed.

Writing on Twitter, the Treasury Board said: "We are sad to report that one of our own, Anja Van Beek, lost her life in Friday's tragic accident in Ottawa. We send our most sincere condolences to her family and all who were close to her."

Besides Thomlinson, Booth and Van Beek, 23 people were injured badly enough to be taken to hospitals by paramedics after the express bus slammed into the station shelter, the roof slicing into the vehicle's upper deck.

Defence officials confirmed that nearly a dozen of those hurt worked at the Department of National Defence, which has set up support services for those affected by the crash as well as their families.

Several of the survivors had limbs amputated, said Ottawa police Const. Chuck Benoit.

Ottawa Mayor Jim Watson acknowledged the horror of the accident and thanked first responders for working in challenging conditions as he signed a book of condolences set up at city hall on Monday.

"This is a very difficult time for our city," Watson said. "Our city is grieving."

The police probe is now focused on speaking with eyewitnesses, combing through the wreckage of the bus, and retrieving data from its "black box" and cameras.

The Ottawa Citizen reported Monday that the driver of the bus, who was arrested and briefly detained by police after Friday's crash before being released without charge, had been on the job for less than a year and involved in two previous collisions.

Watson, however, asked people to refrain from jumping to conclusions.

"We want to find out how this happened and how to ensure it never happens again, but most importantly I don't think it's helpful at all for people to speculate on the reasons," he said.

Yet even as Ottawa police -- and many residents -- were searching for answers to Friday's tragedy, the head of the Transportation Safety Board was weighing in on what she saw as the federal government's failure to increase safety standards for buses.

Five years ago, another Ottawa double-decker bus broke through a warning gate at a rail crossing and hit a moving Via passenger train, killing six people aboard the bus. The TSB investigated that 2013 crash and recommended tougher "crashworthiness" rules for commercial buses.

"Since those recommendations were issued, Transport Canada has undertaken some work," TSB chair Kathy Fox said. "However, significant progress has not yet occurred and the safety deficiencies remain outstanding ... Friday's bus accident in Ottawa, coming on the heels of the 2018 Humboldt bus tragedy and the earlier 2013 Ottawa bus-train accident, not to mention other examples, reinforces the need for Transport Canada to take action."

Fox added that the TSB has offered technical experts to help with the investigation into Friday's crash, but Ottawa police remain in charge of the probe because the Transportation Safety Board is not mandated to investigate road accidents.