Ottawa Police Chief Charles Bordeleau says all three people killed in last week's deadly bus accident were on the bus when it crashed.

Bordeleau says police initially believed two of the victims were on the double-decker bus and a third was on the station platform, but it is now clear all three were on board when it slammed into the station structure on January 11.

Bordeleau says two people were ejected from the bus when it crashed, but they survived and are in hospital recovering from their injuries.

Bruce Thomlinson, Judy Booth and Anja Van Beek, all civil servants working for the federal government, died in the crash, which injured 23 others.

Bordeleau says the police are accepting an offer of technical expertise from the Transportation Safety Board to help determine the cause of the accident.

But he says if any immediate safety concerns are uncovered, they will be relayed to the City of Ottawa and be made public by the police.

He says the only thing ruled out as a cause is impaired driving and that everything else, from weather and road conditions to the driver's history are part of the ongoing investigation.