A timeline of the Quebec City attack and how police responded
What we know about the Halloween attack that left 2 dead, 5 injured
This story is being updated as CBC News and authorities learn more about the events.
When a young man stalked the streets of Old Quebec City on Halloween night, residents began warning each other to stay inside, but it took police more than an hour to alert the public after the first 911 call was made.
Two people were killed and five injured before the 24-year-old suspect was found suffering from hypothermia in the Old Port about a kilometre from where the attacks had begun.
Quebec City police services (SPVQ) are now defending the time it took to warn residents of the danger, and the method used — a pair of tweets just before midnight.
"You have to understand that the situation was evolving and changing very quickly," said Sandra Dion, a spokesperson for Quebec City public security.
"We used the means currently at our disposal to communicate with our citizens."
Though journalists were on the scene interviewing witnesses and police have issued a few details, some of the timeline is still unclear.
Police say it all began when Carl Girouard left his home in Sainte-Thérèse, Que., on Saturday afternoon and drove his black, four-door Saturn roughly 270 kilometres to Quebec City.
Here's a look at how events unfolded.
Around 10 p.m.
The black Saturn is left with its engine still running near Quebec City's landmark Le Château Frontenac hotel.
The exact chronology of what followed is still under investigation.
François Duchesne, 56, the communications and marketing director for the Musée national des beaux-arts du Québec, heads out for an evening jog.
He is stabbed and dies on the sidewalk of du Trésor Street, just across the street from the parked car and behind Old Quebec's Anglican Cathedral.
The assailant attacks and injures another person in front of a year-round Christmas decoration shop.
The assailant then attacks two people walking together on de Buade Street.
They are later found and treated for their injuries on L'escalier Frontenac, which leads from Dufferin Terrace to the Petit Champlain neighbourhood.
A witness who ran to their aid described both as suffering from serious wounds, and said he called 911 shortly after 10:20.
10:20 p.m.
A flood of 911 calls begins. Though police initially said the first call came in at 10:28 p.m., they have since revised that timeline. Quebec City police Insp. André Turcotte tells CBC the initial flurry began about eight minutes earlier.
"People have to understand that when you talk about 10:28, it's after the press conference that happened in the heat of the moment almost as the events were unfolding. After checking all our systems, the calls start coming in around 10:20, 10:21," Turcotte said. "In the seconds that followed, police officers were sent out into the field.
Just before 10:40 p.m.
Hairdresser Suzanne Clermont, 61, is attacked when she steps outside her home on des Remparts Street, which runs north along the top of the old quarter's fortifications, for her usual pre-bedtime cigarette.
Her neighbour Marie-France Rioux, who is an emergency room doctor, runs outside to help, baseball bat in hand.
Despite Rioux's best efforts to deliver aid, Clermont dies from her injuries.
10:52 p.m.
A local taxi company, Taxi Coop, issues an alert to drivers, warning them of the heightened security around Quebec City's Haute-Ville neighbourhood and Old Port.
The alert describes the suspect as between the age of 20 and 30, wearing a medieval costume and carrying a metal sword.
The alert even describes the man's slim build, long hair and approximate height, encouraging drivers to call 911 with any information.
11:57 p.m.
Quebec City police issue a tweet warning the public about a suspect around the National Assembly. The legislature is just outside the walls of Old Quebec.
"According to our preliminary information, the suspect is dressed in medieval clothes," the tweet said.
***ATTENTION*** Le SPVQ recherche activement un homme qui aurait fait de multiples victimes à l’aide d’une arme blanche. Selon nos informations préliminaires, le suspect est habillé en médiéval. Les incidents sont survenus dans le secteur de la colline Parlementaire. Si vu : 911.
—@SPVQ_police11:58 p.m.
Quebec City police issue a second tweet, warning residents to stay indoors.
"Avoid the National Assembly area," the tweet said. "The suspect is still not found. For citizens of the entire city: You are asked to stay inside."
***ATTENTION***| Évitez le secteur de la colline parlementaire. Le suspect n’est toujours pas localisé. Pour les citoyens de l’ensemble de la ville : On vous demande de rester à l’intérieur.
—@SPVQ_policeDion, the city's security spokesperson, says the city has access to Québec en Alerte, a program that sounds out a warning message on platforms like radio, television and mobile devices.
However, only the Sûreté du Québec has the training to use the service at this point, she explains.
The SPVQ says testing the system during an emergency could have compromised the police operation.
In each emergency situation, the SPVQ first has to assess the situation and then "we must deploy the appropriate structure in order to conduct an investigation as effectively as possible."
Then, the teams in place must corroborate the essential information that we will have to transmit to the population.," she said.
"Inaccurate or erroneous information transmitted too hastily could have detrimental effects on our operations, but also mislead citizens and compromise their security," said Dion.
"All SPVQ staff showed great agility in adjusting their actions according to events."
Just after midnight
Police are searching for the suspect on foot.
Carlos Godoy, who lives in the area where the attacks occurred, says police K-9 units searched his backyard as they hunted for the suspect.
Shortly before 1 a.m.
A port officer patrolling the Old Port of Quebec spots who he believes to be the suspect. He phones police.
Police arrest Girouard in the area of the Espace 400e business park on Abraham-Martin Street, about a kilometre from where the assailant's car was left running.
Girouard is taken to hospital to be treated for hypothermia.
1:55 a.m.
Police deliver a media briefing, providing some details about the incident.
4:20 a.m.
Quebec City police confirm on Twitter that the situation is under control.
"According to our initial information, nothing indicates to us that the suspect would have acted for motivations other than personal," the tweet says.
SUIVI DES ÉVÈNEMENTS | La situation est sous contrôle | Le suspect est arrêté et présentement détenu | Selon nos premières informations, rien ne nous indique que le suspect aurait agi pour des motivations autres que personnelles.
—@SPVQ_policePolice encourage people to stay inside Sunday morning as the investigation continues.
Police cordon off 25 crime scenes to search for evidence.
9:30 a.m.
Police deliver a news briefing with more details about the incident and the suspect, saying the incident was likely premeditated and the victims were chosen at random.
Police give the suspect's age and say he was from the North Shore of Montreal.
Quebec City police Chief Robert Pigeon says the man came to the capital "with the intention of doing the most damage possible."
Around noon
Police officers carry out a search of the assailant's home in Sainte-Thérèse, an off-island suburb north of Montreal.
1 p.m.
Quebec City police confirm the identities of the two people killed.
Around 3:40 p.m.
Girouard is charged by video conference with two counts of first-degree murder and five counts of attempted murder.
With files from The Canadian Press, Radio-Canada, Sean Gordon and Kim Garritty