• Twelve people were killed when two masked gunmen opened fire in the offices of the satirical magazine Charlie Hebdo at 11.30 on Wednesday morning – nine journalists with the magazine, a building maintenance worker and two police officers. Laurent Léger, a Charlie Hebdo writer, managed to sound the alarm, calling a friend and telling him: “Call the police. It’s carnage, a bloodbath. Everyone is dead.”

• There were conflicting reports about a sighting on Thursday afternoon of the two brothers – one with possible links to al-Qaida – who are suspected of being behind the attack. The men were at the scene in a getaway car on Wednesday and remain at large. Reuters reported that according to two police sources the manager of a petrol station in Villers-Cotterets in the Aisne region reported seeing suspects Saïd and Chérif Kouachi. There has been no official information given about the whereabouts of the two fugitives. Police investigators were examining the petrol station near Villers-Cotterets and there was a heavy police presence in the nearby town of Crépy-en-Valois, in the metropolitan area of France.

• A third police officer has died after a fatal shooting in a suburb south of Paris on Thursday morning. A man has been arrested and another is on the run after two people, including the officer, were shot in Montrouge, around 5km from the city centre. No link has yet been established with the Charlie Hebdo attack.

• Charlie Hebdo plans to publish a 1m print run for Charlie Hebdo next week after cartoonists and newspapers around the world pledged financial and practical support. Google has announced it will donate £250,000 to to ensure publication.

• A minute’s silence was led by the French persident, François Hollande, at noon on Thursday, which Hollande had declared a national day of mourning. Flags will fly at half mast for three days. Crowds gathered outside Notre Dame cathedral in central Paris, as staff and representatives at Élysée Palace observed the silence, along with those at the UK parliament in London and European parliament in Brussels. A number of media organisations also observed the silence.

• The French prime minister, Manuel Valls, said on Thursday morning there had been several arrests overnight in the hunt for two suspects. All are linked with the two men on the run.

• Police released the names on Wednesday night of three suspects, including pictures of the Kouachi brothers, who are French nationals of Algerian origin. . A vast manhunt continues to find the two men, who are considered to be armed and dangerous.

Facebook Twitter Pinterest Pictures released by French police in Paris of suspects Cherif Kouachi, 32, left, and his brother Saïd Kouachi, 34. Photograph: French police/AFP/Getty Images

• Police also named 18-year-old Hamyd Mourad, who turned himself in at a police station in Charleville-Mézières, a small town in France’s eastern Champagne region, 230km north-east of Paris near the border with Belgium on Wednesday. It was reported he went to police after learning his name was linked to the attacks in the news and social media, said Paris prosecutor’s spokeswoman Agnes Thibault-Lecuivre. She did not specify his relationship with the Kouachi brothers. Friends of the teenager were reported to have said he was in school at the time of the shootings.

• A police source told Reuters one of the suspects had been identified by his identity card, which had been left in the getaway car.

• Chérif Kouachi was sentenced to 18 months in prison in 2008 after being convicted of terrorism charges for helping funnel fighters to Iraq’s insurgency. He said at the time he was outraged at the torture of Iraqi prisoners at the US jail at Abu Ghraib, near Baghdad.

• During the attack witnesses described hearing the attackers shout “Allahu akbar” and “We have avenged the prophet”. Two witnesses said the suspects claimed to be from al-Qaida. One of them specified al-Qaida in Yemen, a group also known as al-Qaida in the Arabian Peninsula.

• Witnesses described the gunmen as calm and professional. They held their weapons in a way which suggested they had some form of military training, although when they arrived at the building they were unsure where to go and what stairwell and floor the offices were on. They forced a female cartoonist to key in the building’s entry code and stormed in to at least two other offices sharing the block, demanding to know the whereabouts of Charlie Hebdo. Once in the Charlie Hebdo newsroom they asked for staff members by name, starting with Charb, before opening fire.

• The attackers escaped the magazine’s offices in a side street off the Boulevard Richard-Lenoir in a car and exchanged fire with police as they fled. They abandoned the car in the 19th arrondissement, near the Porte de Pantin metro station, where they hijacked another car, ordering the motorist out.

• France has raised its terror alert system to the maximum and bolstered security with more than 800 extra soldiers to guard media offices, places of worship, transport and other sensitive areas.

Facebook Twitter Pinterest Some of the victims of the Charlie Hebdo attack: (clockwise from top left), Charb, Honoré, Bernard Maris, Tignous, Georges Wolinski and Cabu. Photograph: Guim

• The 12 victims of the attack have been identified. They are: Charb – whose real name was Stéphane Charbonnier, 47, artist and publisher of Charlie Hebdo; Cabu – whose real name was Jean Cabut, 76, Charlie Hebdo’s lead cartoonist, who was honoured with the Légion d’honneur, France’s highest civil decoration, in 2005; Georges Wolinski – Tunisian-born artist, 80, who had been drawing cartoons since the 1960s, and worked for Hara-Kiri, a satirical magazine considered a forerunner to Charlie Hebdo; Tignous – whose real name was Bernard Verlhac, 57, was a member of a group of artists called Cartoonists for Peace; Bernard Maris – known as “Uncle Bernard”, 68, was an economist and wrote a regular column for Charlie Hebdo; Philippe Honoré, AKA Honoré, 73, a cartoonist who had worked for Charlie Hebdo since 1992 and drew the last cartoon tweeted by the weekly only moments before the massacre; Michel Renaud – a former journalist and political staffer who founded a cultural festival, who was visiting the Charlie Hebdo offices from Clermont-Ferrard; Mustapha Ourrad – a copy editor for Charlie Hebdo of Algerian descent; Elsa Cayat – Charlie Hebdo analyst and columnist; Frederic Boisseau – building maintenance worker; Franck Brinsolaro – 49-year-old police officer appointed to head security for Charb and father of a one-year-old girl; Ahmed Merabet – 42, a French Muslim police officer and member of the 11th arrondissement brigade.

Facebook Twitter Pinterest About 15,000 people take part in a vigil in Lyon, France to mourn the 12 people killed. Photograph: Inediz/Inediz/Demotix/Corbis

• Large, spontaneous gatherings materialised in public squares across France on Wednesday evening to condemn the attacks and pay tribute to the victims.

• Charlie Hebdo has been the subject of violent attacks in the past, following its publication of cartoons of the prophet Muhammad. Its offices were firebombed in 2011, and recent threats have also been made against it and other media groups. Riot police were deployed to its offices in 2012 after it published more Muhammad cartoons, including images of him naked.

• Charlie Hebdo’s editor-in-chief, Gérard Biard, escaped the attack because he was in London. He expressed his shock and said the magazine had had no specific threats of violence. “A newspaper is not a weapon of war,” he said.