They were a career criminal and his girlfriend, a failed rapper and his older brother. At least two had spent time in French jails.
All seemed to fit a now-familiar profile: Disenchanted young Europeans of working-class immigrant backgrounds who become radicalized through exposure to Islamist extremists.
All were well-known to authorities, but somehow fell through security cracks in a nation that is home to Europe's largest Muslim population — and exports a steady stream of Islamic militants abroad.
The brothers, Cherif and Said Kouachi, French born but of Algerian heritage, were on U.S. no-fly lists, and Yemeni officials had reportedly passed on intelligence that Said, 34, had trained with militants in Yemen. The younger sibling, 32, had been jailed for recruiting Islamic militants for Iraq.
Still, in a nation with strict gun-control laws, the siblings and their ex-convict confederate were able to obtain an arsenal of heavy arms and cut a swath of terror through Paris for three days, roiling the nation and killing at least 17 people — 12 on Wednesday at the Paris offices of the satirical magazine Charlie Hebdo, long in extremist crosshairs for mocking Islam; a female police officer gunned down Thursday in southern Paris; and four hostages who police say were executed Friday at a kosher grocery on the city's eastern periphery.
The rampage ended abruptly Friday during a pair of near-simultaneous police raids that left three attackers dead. But many questions — and concerns — remain.
Chief among them is whether the assailants acted on their own or under direction of Al Qaeda or another transnational terrorist network, and whether additional attacks are likely to occur in a nation that is home to multitudes of Muslim immigrants, many of whom live in overcrowded, impoverished suburbs.
Counter-terrorism experts say France faces an imposing terrorist threat for a country of 66 million.
"The French are pretty aggressive at monitoring" suspected terrorists inside France, said Seth Jones, an expert on Al Qaeda at Rand Corp.
That said, more than 1,000 French citizens are believed to have traveled to fight alongside Islamist rebels in Syria and Iraq, according to official estimates here, leaving French intelligence services with an inordinately large number of people to track. "No major country has that kind of threat," Jones said.
By comparison, the U.S., which has a much larger budget for its intelligence services than France does, believes that about 100 Americans have traveled or attempted to travel to join the civil wars in Iraq and Syria.
France remains on the highest state of alert. Officials have vowed to maintain a beefed-up police presence across the country. But analysts warn that last week's attacks could be a prelude to others.
"My great belief is that Charlie Hebdo is but the first stage of a long" campaign, Jean-Pierre Filiu, a Middle East expert at the Paris Institute of Political Studies, known as Sciences Po, wrote in a comment on a French television website.
France is planning a national rally of reconciliation Sunday under extremely tight security. But officials still have much to explain. French Prime Minister Manuel Valls has publicly acknowledged "failings" in intelligence that contributed to France's worst terrorist attacks in half a century.
It remains unclear to what extent, if any, the attackers were under police surveillance before last week's strikes. Some reports have suggested that the nation's anti-terrorist security regimen is severely overtaxed.
But there is no question that the assailants were on the law enforcement radar.
Amedy Coulibaly, 32, the gunman who seized the kosher market on Friday and was killed in the police assault, had a long history of jail time for various convictions, including armed assault, according to reports here. Coulibaly is reported to have converted to Islam while serving time.
Police were still seeking his girlfriend, Hayat Boumeddiene, 26, who, according to reports Saturday, left France for Turkey before the attacks. What role she may have played in the Paris mayhem remains murky.
In a 2010 interview with police, according to the French daily Le Monde, the onetime cashier from a working-class Paris suburb questioned her boyfriend's dedication to his adopted creed.
"Amedy is not religious enough," Boumeddiene reportedly complained to police. "He likes to have fun and all of that."
French authorities say they have documented links between the couple and the Kouachi brothers, responsible for the attack on the magazine offices. Prosecutors say that Boumeddiene had exchanged hundreds of phone calls with the partner of Cherif Kouachi.
Some reports suggest that Coulibaly met the younger Kouachi, a onetime aspiring rapper, in jail.
The two men were linked to a plot to spring an imprisoned Islamist, Smain Ait Ali Belkacem, who was serving a life term in connection with the 1995 Paris train bombings that left eight dead and dozens injured. Kouachi was not prosecuted, but Coulibaly was jailed for his involvement in the plot.
Djamel Beghal, a militant convicted of planning an attack on the U.S. Embassy in Paris more than a decade ago, became a kind of mentor for the younger Kouachi and Coulibaly, according to French news reports.
Cherif Kouachi was convicted in 2008 of helping to funnel volunteers to fight in Iraq during the U.S.-led war. He was part of a ring known as Buttes-Chaumont, after a park in the brothers' edgy former neighborhood in northeastern Paris. Several militants close to Kouachi were also convicted in the case, ending the network.
Said Kouachi was believed to have traveled to Yemen and returned to France in 2011, where he "went dark," according to a Western government official familiar with the case.
Western intelligence officials who were tracking Kouachi did not find indications that he was still communicating with contacts in Yemen.
Intelligence officials theorized that Kouachi lost touch with Al Qaeda's affiliate in Yemen after the group's director of external operations, American-born cleric Anwar Awlaki, was killed in a U.S. drone strike in September 2011.
Over the next few years, French authorities didn't see any signs that Kouachi was planning an attack. As a result, at some point last year, French authorities decided to reduce Kouachi's case to a lower priority for surveillance, the official said.
But, as last week's events dramatically illustrated, the Kouachi brothers and Coulibaly were by no means finished.