As more information emerged about the men who detonated bombs in Brussels on Tuesday, it became clear that they were members of a militant cell that was also behind November's attacks in Paris that killed 130.
Here's a brief rundown of the major players involved in each attack, and the connections between the two.
LINKED TO BOTH ATTACKS
Najim Laachraoui | 24 | Dead
Laachraoui was one of the suicide bombers at the Brussels airport, a U.S. official with knowledge of the investigation told the Los Angeles Times.
Laachraoui was also suspected of helping plan the Paris attacks. He is believed to have made the explosives that were set off around the city and to have helped an alleged key participant in the attacks, Salah Abdeslam, during Abdeslam's four months on the run.
Laachraoui traveled to Syria in February 2013, and was on a list maintained by authorities to track Belgian citizens who had traveled there. He is known to have used fake Belgian ID cards identifying him as Soufiane Kayal while traveling in Europe. His DNA was found in houses in the Brussels neighborhoods of Auvelais and Schaerbeek that authorities believed were used in the Paris terrorism plot.
A U.S. official told The Times that Laachraoui had been on an American terrorism watch list.
Khalid El Bakraoui | 27 | Dead
Bakraoui died detonating a bomb in the Maelbeek Metro Station.
He is the brother of Brahim Bakraoui; both were Belgians of Moroccan descent. A U.S. official told the Los Angeles Times that the brothers had been on an American terrorism watch list.
Khalid El Bakraoui had been sentenced to five years in prison for his part in an armed carjacking, Belgian media reported.
He is also believed to have rented apartments used by the Paris attackers, according to Belgian media.
Salah Abdeslam | 26 | In custody
Abdeslam grew up in Belgium. A top suspect in last year's Paris attacks that left 130 people dead, he was charged with "terrorist murder" by Belgian authorities. After the Paris attacks, he was the subject of an international manhunt until March 18, when he was shot in the leg and arrested in a police raid. He is being held in isolation in a Belgian jail.
A French prosecutor said Abdeslam had planned to detonate a suicide bomb at Stade de France on Nov. 13 but backed out at the last minute.
He was a childhood friend of Abdelhamid Abaaoud, the suspected mastermind of the Paris attacks.
LINKED TO BRUSSELS ATTACKS
Brahim El Bakraoui | 29 | Dead
Bakraoui is the brother of Khalid El Bakraoui and was a Belgian of Moroccan descent. He died in the suicide bombing at the Brussels airport, along with Najim Laachraoui.
He had served part of a nine-year prison sentence -- handed down in 2010 -- for his participation in an armed robbery during which a police officer was injured. It was unclear why he was released before completing his term.
In 2015, Bakraoui was deported from Turkey on suspicion of being a foreign fighter involved in the conflict in neighboring Syria. Turkish officials have said they notified Belgium, raising concerns that Belgian officials overlooked warning signs.
Belgian officials downplayed his centrality to the Brussels plot. “He's only one of the perpetrators, and not even the most enterprising one,” Justice Minister Koen Geens said. “He was not the mastermind of this affair.”
In a trash bin at a flat in Schaerbeek after the Brussels bombings, investigators said, they found a laptop containing a kind of last testament from Bakraoui.
“I don't know what to do, I am in a hurry,” read the declaration. “I am on the run. People are looking for me everywhere. And if I give myself up, I will end up in a cell.”
Unidentified suspect | Likely still on the run
Investigators said one man escaped after abandoning his bomb at the airport.
An airport camera screen grab, made and released March 22 by the Belgian Federal Police, shows this man pushing a luggage cart and walking alongside two of the bombers in the Brussels Airport shortly before the explosions. Some media reports have taken to calling him the "man in white."
A man identified as Fayal C. was charged with terrorism offenses on March 26, and Belgian media reported that he was the surviving airport bombing suspect.
Authorities, however, never publicly alleged that the man was the third airport bomber. He was released on March 29 due to a lack of evidence, seeming to signal that the third airport attacker remains a fugitive and that the massive manhunt for him will continue.
On April 8, a French police official said this man is believed to be Paris attacks suspect Mohamed Abrini, who was arrested that same day in Belgium.
Unidentified suspect | At large
A possible fifth suspect was captured on closed-circuit TV film as he carried a large bag in the subway alongside one of the suicide bombers, according to Belgium TV network RTBF and French newspaper Le Monde.
LINKED TO PARIS ATTACKS
Abdelhamid Abaaoud | 27 | Dead
Abaaoud, the Belgian son of a Moroccan immigrant, was killed in a November police raid in France. He may have been the mastermind of the attacks in Paris. He has also been identified as a suspect in a variety of thwarted plots to attack churches, trains and police officers in Belgium and beyond.
In an active social media life since leaving Belgium for Syria in 2013, Abaaoud was first seen on the Internet as an online recruiter of Europeans. He boasted of the glory of jihad to an audience of disaffected young European Muslims like himself, and he taunted European officials for being unable to catch him.
"A Muslim should not fear the bloated image of the crusader intelligence," he said in an interview published by the Islamic State's in-house magazine in February 2015. "My name and picture were all over the news, yet I was able to stay in their homeland, plan operations against them, and leave safely when doing so became necessary."
Bilal Hadfi | 20 | Dead
Hadfi and two unidentified men blew themselves up outside the Stade de France in Paris.
Hadfi had also been living in Belgium but went to Syria in February 2015.
Brahim Abdeslam | 31 | Dead
Abdeslam died on the night of the Paris attacks when he detonated a suicide vest outside a restaurant. He lived in Belgium and was the brother of Salah Abdeslam. He is believed to have used the pseudonym Amine Choukri.
Brahim spent time in territory controlled by Islamic State and trained in the group's capital of Raqqah, according to what an activist group, known as Raqqah is Being Slaughtered Silently, told the Associated Press.
He reportedly grew up in the Brussels neighborhood of Molenbeek and, along with his brother Salah, owned a bar called Les Beguines.
Chakib Akrouh | 25 | Dead
Officials identified Akrouh as one of the attackers who opened fire at bars and restaurants in Paris on the night of the attacks there. He reportedly had ties to the Molenbeek neighborhood in Brussels.
Akrouh killed himself with a bomb five days after the Paris attacks during a police raid in Saint-Denis.
Foued Mohamed Aggad | 23 | Dead
Aggad attacked the Bataclan concert hall with two other suspects.
He lived in Strasbourg, France, and went to Syria to join Islamic State militants in late 2013, but managed to reenter France, French officials said.
Mohamed Abrini | 31 | In custody
Abrini grew up in the Brussels neighborhood of Molenbeek. Footage shows him at a gas station with Laachraoui two days before the attacks in Paris. They were driving a black Renault Clio, the same car that was used in the attacks.
He was arrested in Belgium on April 8, Paris police officials confirmed. He is also believed to be the man in the hat who was last seen leaving the Brussels airport after the double explosion there.
Omar Ismail Mostefai | 29 | Dead
Mostefai attacked the Bataclan Concert Hall in Paris with two other men armed with assault rifles and explosive vests. He was born near Paris, and neighbors where he lived in Chartres reported that he started becoming radicalized about five years before the attacks.
Mostefai had reportedly been on a watch list as someone susceptible to radicalization but not yet requiring extensive surveillance. He was known to police as a small-time criminal whose offenses included driving without a license and insulting behavior toward authorities.
A senior Turkish official told the Associated Press that in 2013, Mostefai entered Turkey, a common pathway to Syria for foreign fighters hoping to join Islamic State. The newspaper Le Monde said Mostefai probably spent the winter of 2013-14 in Syria.
Samy Amimour | 28 | Dead
Amimour attacked the Bataclan Concert Hall with two other men. He was reportedly raised in a Paris suburb.
Amimour was one of three friends arrested in 2012 on suspicion of plotting to travel to Yemen or Afghanistan to take part in violent jihad, according to the French newspaper Le Parisien. He was put under judicial supervision but disappeared in the fall of 2013.
He apparently later made it to Islamic State-held territory, where he appeared in a video that showed several of the future Paris attackers standing behind captives who were either beheaded or shot.
"Soon on the Champs-Elysées," Amimour said in the video while holding a victim's head aloft, according to the Associated Press.
Unidentified | Dead
This unidentified man blew himself up outside the Stade de France stadium with two other attackers.
Fingerprints taken from one the suicide bombers outside the stadium matched those of a man who arrived in Europe via Greece in October.
A Syrian passport was found near the man’s body, identifying the holder as Ahmad Al Mohammad, 25, from Idlib, Syria. It's not clear if the passport or the name was authentic. According to some reports, Mohammad was a Syrian soldier who died some time ago.
French authorities circulated this photograph asking for help identifying the dead attacker.
Unidentified | Dead
This man is a second unidentified attacker outside the Stade de France.
9 a.m. April 8: This article was updated with information about the arrest of Mohamed Abrini.