A timeline of the Quebec City attack and how police responded

This story is being updated as CBC News and authorities learn moreabout 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 warnresidents 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," saidSandra Dion, a spokesperson for Quebec Citypublic security.

"We used the means currently at our disposal to communicate with our citizens."

Though journalists were on the scene interviewing witnessesand police have issued a few details, some of the timeline is still unclear.

Police say it all began when Carl Girouardleft his home inSainte-Thrse, Que., on Saturday afternoon and drove his black, four-door Saturnroughly 270 kilometresto Quebec City.

Here's a look at how events unfolded.

Around 10 p.m.

The black Saturnis leftwith its engine still running near Quebec City's landmarkLeChteau Frontenac hotel.

The exact chronology of what followed is still under investigation.

Franois Duchesne, 56, the communications and marketing director for the Muse national des beaux-arts du Qubec, heads out for an evening jog.

He is stabbed and dies on the sidewalk of du Trsor 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 thenattacks two people walking togetheron deBuade Street.

They are laterfound and treated for their injuries onL'escalier Frontenac, which leads from Dufferin Terrace to the Petit Champlain neighbourhood.

A witness who ranto their aid described both as suffering from serious wounds, and said he called 911 shortly after 10:20.

10:20p.m.

A flood of 911 calls begins. Though police initially said the first callcame in at 10:28 p.m., they have since revised that timeline. Quebec City police Insp. Andr Turcotte tells CBC the initial flurry beganabout 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, isattacked when shestepsoutside her home on desRempartsStreet, 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 diesfrom 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 describesthe suspect as between the age of 20 and 30, wearing a medieval costume and carrying a metal sword.

The alert even describesthe man's slim build, long hair and approximate height, encouragingdrivers to call 911 with any information.

11:57 p.m.

Quebec City police issue a tweet warning the public about asuspect 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.

11:58 p.m.

Quebec City police issue a second tweet, warning residents to stay indoors.

"Avoid the National Assemblyarea," the tweet said. "The suspect is still not found. For citizens of the entirecity: You are asked to stay inside."

Dion, the city's security spokesperson, says the city has access to Qubec en Alerte,a program that sounds out a warning message on platforms like radio, television and mobile devices.

However, only theSret du Qubec 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 firsthas toassess 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 Quebecspotswho he believesto be the suspect. Hephonespolice.

Police arrestGirouardin the area of the Espace 400e business parkon Abraham-Martin Street, about a kilometre from where the assailant's car was left running.

Girouardis taken to hospital to be treated for hypothermia.

1:55 a.m.

Police deliver a media briefing, providing some details about the incident.

WATCH | Quebec City police deliver a early morning update:

Quebec City police give update on Halloween attack

4 years ago

Duration 1:49

SPVQ officer tienne Doyon speaks early Sunday morning from the scene (in French only).

4:20 a.m.

Quebec City police confirmon Twitterthat 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.

Police encouragepeople to stay inside Sunday morning as the investigation continues.

Police cordonoff 25crime scenes to search for evidence.

9:30 a.m.

Police delivera 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 saysthe 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-Thrse, an off-island suburb north of Montreal.

1 p.m.

Quebec City police confirm the identities of thetwo people killed.

Around 3:40 p.m.

Girouardis charged by video conference with two counts of first-degree murder and five counts of attempted murder.