Three days after French police shot dead the trio of men responsible for the terror attacks that killed 17 people in Paris, the authorities and various media reports have compiled information that, when pieced together, details the lives the perpetrators led and their connections to each other.

Brothers Cherif Kouachi, 32, and Said Kouachi, 34, were the black-masked gunmen armed with automatic weapons that murdered 10 journalists and two police officers at the offices of satirical magazine Charlie Hebdo on Wednesday.

Amedy Coulibaly, 32, killed four people and took several hostages Friday at a Hypercacher kosher supermarket in Vincennes, a southeastern Parisian suburb, after gunning down a policewoman in Montrouge the previous day.

All three died Friday after simultaneous hostage crises. Police killed the the Kouachis after they emerged firing their weapons from a warehouse where they'd been holed up. Coulibaly was shot to death when police stormed the Hypercacher shortly after the shootout with the Kouachi brothers.

Coulibaly claimed he was linked to the Kouachis. He called French news channel BFMTV from the supermarket and said that he "synchronized" operations with the brothers. It's unclear if the men acted on behalf of terror groups overseas.

Coulibaly told BFMTV that he received instructions directly from the Islamic State (IS), an armed extremist group that operates in Iraq and Syria. A video emerged Sunday that appears to show Coulibaly pledging allegiance to IS, and again claiming that he planned the attacks with the Kouachis.

Cherif Kouachi also spoke Friday with BFMTV and said he received instructions from al Qaeda in the Arabian Peninsula (AQAP). Witnesses to the Charlie Hebdo attack told French media that shortly before getting into their getaway car one of the assailants shouted, "Tell the media that it is al Qaeda in Yemen!"

AQAP has not yet claimed responsibility for the attacks. IS and al Qaeda are rivals and have clashed in Syria on numerous occasions, making it unlikely that they would plan an attack together.

All three men were born in France. The Kouachis had Algerian parents who died when they were young.

Cherif spent part of his childhood in an orphanage in Rennes, in northwest France, where he studied to become a personal trainer. In recent months, the brothers shared an apartment in Gennevilliers, a middle-class suburb north of Paris with around 40,000 residents and a sizable Muslim population. Cherif delivered pizzas for a living.

Coulibaly was born in Juvisy-sur-Orge, one of 10 children in his family. He had a history of petty crime, including several drug offenses. In 2009 he had a temporary job in a Coca-Cola plant and met then-President Nicolas Sarkozy at the Presidential Elysee Palace during an employment initiative designed to create work for young people. He spoke with a Le Parisian reporter at the time, who described him as nervously admitting that he wouldn't know what to say to Sarkozy, and that his nine sisters asked him for photos of the occasion and the president's autograph.

Despite these mundane backgrounds, both Coulibaly and the Kouachis had extremist pasts. The brothers were marked for "covert surveillance" on a Europe Union-wide register, German Interior Minister Thomas de Maiziere told German public service broadcaster ARD. The Kouachis were also reportedly on the US "no fly list," and included in TIDE, a US security database that contains information on more than a million terrorism suspects.

Intelligence sources have reportedly said that France's counterterrorism agencies did not consider the brothers to be priority suspects — though they were under police surveillance.

All three men had connections to the so-called "Buttes-Chaumont network," a jihadist group also known as the "19th Arrondissement network" that recruited fighters to battle the US-led coalition forces that invaded Iraq in 2003. The network takes its name from a park in Paris where radical French-Algerians met and trained.

Cherif was jailed in 2005 after attempting to travel to Iraq via Syria to fight with Islamic militants. While behind bars, Cherif reportedly met Coulibaly and Djamel Beghal, a militant who was serving a 10-year sentence for his role in a 2001 plan to bomb the US embassy in Paris.

After his release, the younger Kouachi, then an aspiring rapper, was featured in a 2005 local television documentary about the recruitment of young Islamic extremists. He was jailed again in 2008 for a three-year stretch for sending jihadists to fight in Iraq, but only served 18 months of his sentence.

A neighbor of the Kouachi brothers in Genneviliers told the BBC that Cherif wasn't "aggressive" or a "crazy zealot," but a "well-behaved, friendly, polite, clean-looking" man willing to "help old and disabled people." Another neighbor told the_Globe and Mail _on Friday that the brothers kept a large "cache of arms" inside their residence.

Photo via Storyful

In 2010, Cherif was detained because of his links to a plot to break convicted terrorist Smain Ait Ali Belkacem out of prison, where he is still serving a life sentence for the 2002 Paris metro bombing. Police found al Qaeda propaganda videos when they searched Cherif's home, along with evidence that he perused jihadist websites. His brother Said was also a suspect in the case.

Coulibaly was also involved in the prison break plot, according to _Le Monde, _and was sentenced to five years in prison, where he and Cherif met again.

In 2011, meanwhile, Said travelled to Yemen where, according to a Yemeni intelligence source who spoke with Reuters_, _he met and subsequently received funding from Anwar al-Awlaki, an al Qaeda preacher who was born in the US and killed by an American drone strike in September 2011.

American and European sources told Reuters on Friday that Said spent several months training with AQAP in Yemen. Cherif told BFMTV that he also travelled to Yemen.

A French drug dealer acquainted with Coulibaly told the Associated Press that he was "totally shocked" by the attacks. The dealer said Coulibaly never prayed or spoke about Islam.

The authorities are currently hunting for Hayat Boumeddiene, Coulibaly's partner and suspected accomplice. Turkish Foreign Minister Mevlut Cavusoglu said Monday that Boumeddiene was in Istanbul five days before the Paris attacks. She allegedly crossed the border into Syria on January 8 — the same day that Coulibaly killed a police officer in Montrouge.

Boumeddiene is also linked to the Kouachis. France's chief prosecutor, Francois Molins, told reporters that she exchanged over 500 phone calls with Cherif's wife in 2014.

VICE News' __Katie Engelhart contributed to this story.