What We Know About Some of the Alleged Attackers Behind Paris Plot

Friday was the deadliest single attack in French history since WWII.

— -- Authorities have indicated they suspect at least 10 people, including seven suicide bombers, had direct involvement in the Paris attacks Friday night that claimed at least 129 lives -- the deadliest single attack in French history since the Second World War.

Two people have been arrested in Belgium and charged with terror-related offenses, officials there say. Another man is on the loose, believed to be in Belgium and yet another, thought to be in Syria, has recently been identified as the “mastermind” of the attacks.

Here is what we know so far about some of the people allegedly involved. Others have not been publicly identified.

Abdelhamid Abaaoud Named as Suspected 'Mastermind'

French officials say Abdelhamid Abaaoud, who has been prominently featured in ISIS videos released online, played a key role in Friday’s deadly massacre. Abaaoud is reportedly from the Brussels neighborhood of Molenbeek, the same neighborhood in Belgium that is home to at least two of the Paris suicide bombers.

Abaaoud was previously linked to smaller terror plots in Europe, and after a police raid in which two suspected extremists were killed in January, he told an ISIS magazine he was able to escape capture and slip into Syria. He’s believed to still be there, where one French official said he’s considered a “high-profile terrorism figure.” French media first named Abaaoud in connection to the Paris attack.

The Brothers: A Suicide Bomber and a Fugitive

French authorities are desperately hunting for a man identified as Salah Abdeslam, who police said Sunday was “involved” in the massacre and is on the loose.

Early this morning, a law enforcement source told ABC News Abdeslam had been tracked to a building in Molenbeek, where he was surrounded by police, but later police found he wasn't there.

Brahim Abdeslam, a brother of Salah, was a suicide bomber who died on Boulevard Voltaire, officials said.

Mohammed Abdeslam, another brother of Salah and Brahim, was initially detained in Molenbeek but released.

"I was not tied in any way to anything that happened Friday," Mohammed said at a news conference. Mohammed said he had an alibi for Friday night.

Mohammed said he "didn't notice anything among my brothers," adding that, "they acted normally."

"I can't tell you how or why," he said. "We are an open family, we've never had issues with the law."

"My parents are shocked," Mohammed said.

"Salah hasn't been heard by authorities and we don't know all the facts," he explained. "We don't know where he is, whether he has the courage to turn himself in."

In response to the attacks, Mohammed said, "We never thought that one of our brothers was part of this attack. We are thinking about the families of the victims. But we should also remember that my mother, one of her sons is dead, and she is affected by that."

Ismail Mostefai ID'd as Suicide Bomber

Suicide bomber Ismail Mostefai, a 29-year-old French citizen, was described as a petty criminal. French authorities identified Mostefai as a potential radical years ago, but he was never charged with a serious crime.

Turkey also claims it twice warned France about Mostefai as early as last October, according to a report by Turkey’s state news agency and confirmed to ABC News by the Turkish Prime Minister’s office. A Turkish security official quoted by Turkey’s Anadolu Agency said that France did not respond to either warning.

Suicide Bomber with Syrian passport

Another of the bombers appeared to have used a Syrian passport and a fake name to slip into Europe disguised as a refugee. The passport was found on the bomber's body outside the Stade de France stadium.

Greek authorities released a report over the weekend saying the man came on a boat with nearly 200 other people from Turkey to the Greek island of Leros in early October. European authorities say he eventually made his way through the Balkans and into Austria before disappearing.

Bilal Hadfi, A Stadium Bomber

Officials told ABC News one of the stadium bombers was identified as Bilal Hadfi.

Samy Amimour, A Concert Hall Bomber

Samy Amimour was one of the Bataclan concert hall bombers, said French officials.

Amimour, born in 1987 in the Paris suburb of Drancy, was known to French intelligence, a French prosecutor’s spokeswoman told ABC News. Amimour was indicted in 2012 for involvement with terrorist activity and violated the terms of his indictment in 2013, the spokeswoman said, and was up to now facing an international arrest warrant.

CORRECTION: This report has been updated to say that two suspected extremist reportedly were killed in the January shootout by police. The original report erroneously said two policemen had been killed in that incident.