WATCH: No easy answers to questions swirling around fatal Ottawa bus crash: police chief

Ottawa police say there will be no quick or easy answers to questions swirling around a deadly bus crash on a busy city route.

Chief Charles Bordeleau describes the investigation into the crash, which killed three and injured 23 more, as a painstaking process.

He says the bus was at or near its full capacity of 90 passengers at when it slammed into a bus shelter on Friday afternoon, and police will have to interview everyone on board at the time.

Officers have already spoken with the bus driver, who was arrested shortly after the collision, but released unconditionally pending further investigation.

He says they will also have to survey the wreckage using drones, go over video and data gathered from the bus and bystanders.

Police say the majority of the patients injured in the crash have been released from hospital, with one remaining in critical condition, six listed as serious and four considered stable.

There are no plans to release the names of the victims at this time. 

- With a file from NEWSTALK1010