Brussels – Belgium’s federal general prosecution announced on Friday that it was charging a 30-year-old Belgian detainee of being linked to the 2015 Paris attacks after he was initially arrested for being involved in the March 22, 2016 Brussels assault.

Yassine Atar, 30, was formally charged “on account of terrorist assassinations and of participation as a leader in the activities of a terrorist group,” a statement from the Belgian prosecutor’s office said.

Yassine was arrested just days after the 2016 Brussels attacks, found in possession of key to a hideout used by the jihadists that carried out the attacks in both European cities, Belgian broadcaster RTL has reported.

He was suspected at the time of personally preparing to carry out a terrorist attack.

Salah Abdesalam, the only surviving perpetrator of the Brussels attack, had also used the hideout. He was arrested in March 2016.

Yassine is the brother of Oussama Atar, 32, who remains at large and is believed to be one of the commanders of the attacks both in Brussels and in Paris, that were claimed by ISIS.

The Atars are cousins of the El Bakraoui brothers who blew themselves up in the Brussels airport and metro attacks.

In April, Brussels announced the arrest of three suspects in raids in Spain’s Barcelona on suspicion of being linked to Yassine Atar and his brother.

The authorities had hoped that the suspects would help in the investigation in the Brussels attacks that left 32 people dead and 300 wounded.

Trusted sources said that Oussama Atar was the target of the Barcelona raids that were carried out in cooperation between Belgian and Spanish authorities,

After being arrested in Iraq in 2004 following the US-led invasion of the country, Oussama Atar spent time in various jails including the notorious Abu Ghraib prison used by American forces.

Released in 2012, he returned to Belgium where intelligence and police forces have faced fierce criticism about the development of extremist networks in Brussels.

In a letter to his mother, the elder Oussama Atar, who is believed to be based in Syria, denied investigators’ claims that he was the “mastermind” of the Brussels and Paris attacks.

Belgium has been on high alert since March 22 last year when suicide bombers attacked Zaventem airport and the Maalbeek metro station.

The attacks were led by an ISIS cell that was also responsible for the carnage in Paris in November 2015 that killed 130 people.