It's been two days since a massive explosion tore through a tanker truck manufacturer in Ottawa's south end, and the complex, multi-faceted investigation is only just getting started.
Developments have been flying fast and furious since the first 911 calls came in at around 1:30 p.m. Thursday.
While it will likely be some time before there's a firm explanation as to what caused the explosion, some details have been confirmed — including that one person is dead and five more are missing and presumed dead.
Here's what we know so far, and when we learned it.
At around 1:30 p.m., people start calling 911 about a massive explosion at an industrial business on Merivale Road just north of West Hunt Club road.
Some callers report flames 15 to 18 metres high at the site, while witnesses tell CBC they heard loud bangs and booming noises.
Firefighters on scene discover the building is engulfed in flames and the roof and walls are collapsing. They begin fighting a defensive battle against the fire.
Just after 2 p.m., Ottawa police tweet that people have been injured in an explosion and fire on the 1900 block of Merivale, and a stretch of Merivale has been blocked off.
CBC reporters arrive on scene — or as close as they can get — shortly afterward to find officers directing traffic, emergency vehicles racing by, and smoke billowing in the distance.
Acting fire chief Paul Hutt gives his first update from the scene at around 3:30 p.m., telling reporters two people have been taken to hospital with undisclosed injuries. At roughly the same time, The Ottawa Hospital says in a statement they actually have three people in their care.
Ottawa Mayor Jim Watson, meanwhile, discloses the location of the fire as Eastway Tank Pump & Meter Ltd., a manufacturer of custom tank trucks.
About one hour later, Hutt gives a second update, saying the fire is still active and they need to bring in heavy equipment to suppress it. He says crews are sucking up any contaminated water and taking air quality samples, and there's no danger to nearby residents.
Paramedics, meanwhile, confirm three people are indeed in hospital — two in critical condition, one in stable condition.
Shortly after 5:30 p.m., Ottawa Fire Services announces a "family reunification centre" has been set up at Woodvale Pentecostal Church in order to reunite employees with their families.
Firefighters officially bring the blaze under control at 5:48 p.m.
Ottawa police, fire and paramedics issue a joint news release just before 7 p.m., urging all workers and their family members to head to the reunification centre to make sure everyone is accounted for. They say emergency crews are still searching the fire scene and watching for any flare-ups.
Merivale Road reopens at around 7:30 p.m.
Knoxdale-Merivale Coun. Keith Egli, who represents the area, provides an early-morning update to CBC Radio's Ottawa Morning. He says he visited the reunification centre Thursday night but didn't know if all workers were accounted for.
At a 9 a.m. press conference, nearly 20 hours after the explosion, police officially confirm five people who were in the building at the time of the explosion are missing and believed to be dead.
Police also say one of the three men taken to hospital Thursday had died. Another is in stable condition, while the third was released from hospital.
Ottawa police announce the arson unit will be the lead investigators for the force, although they do not say whether they believe the explosion and fire were caused by a deliberate act.
Ontario's Office of the Chief Coroner confirms it would help with the investigation shortly before 10 a.m.
Just before noon, Eastway Tank president Neil Greene issues a statement saying he is "completely [devastated]" and his company will co-operate with all investigations. He says they want to "get to the bottom of what happened."
Another city councillor, Tim Tierney, tells CBC News at around 1 p.m. about how he was nearby when the explosion occurred. He says he initially thought it was an earthquake.
Ontario's Ministry of Labour says around 4:30 p.m. they will conduct a parallel investigation.
A spokesperson says they issued four orders against Eastway Tank in 2017, related to issues like ventilation, welding and hazardous chemicals. They were fully complied with.
The Ministry of the Environment, meanwhile, sends an email just before 5:30 p.m. to say that clean-up efforts are still taking place and that environmental risks to the community are low.
Drone footage captured by CBC roughly around that time also shows work continuing at the fire site.
On Friday evening, the identity of one of the victims, 57-year-old Rick Bastien, was confirmed to CBC News by his son.
Josh Bastien said his father, a long-time Eastway employee listed on the company's directory as a welder/fabricator/mechanic, was a "stand-up guy" who was "loved by everyone that came across him."
A former Eastway employee himself, Bastien also shed light on the other five victims, saying they were his friends and calling them all "good people."