Ottawa Police Chief Charles Bordeleau confirms TSB has accepted a request from the City to aid in the investigation into Friday's bus crash at Westboro Station, which killed three people and injured 23 others.

At a press conference at Ottawa Police headquarters, Bordeleau revealed the TSB’s involvement, saying its experts will be providing technical assistance. The Police will continue to lead the investigation into the crash.

Bordeleau says the investigation will be divided into two parts: the first to determine if a criminal offence took place, the second to reconstruct the crash and determine the cause and any contributing factors.

The Route 269 double-decker bus slammed into the roof of the Transitway shelter at Westboro Station Friday afternoon, cutting through the right side of its upper level.

The bus driver was initially arrested after the crash but has since been released unconditionally.

Bordeleau said police are looking at “all factors” with respect to the driver, including driving record and actions on the day of the crash.

The bus remains held in a “secure location,” Bordeleau said.

Ottawa Police also corrected an earlier explanation, saying all three fatalities stemmed from people who were on the bus. Previously it was thought that one of the deaths was a person on the platform waiting for the bus, but Bordeleau said this was found not to be true.