The Belgian Police Monday released Fayçal C after it could not gather evidence to prove his involvement in the terror attacks at the Brussels airport and metro, according to reports.

The man dressed in white and a hat was seen in the CCTV footage at the airport, alongside two men who had blown themselves up in the departure hall of the Zaventem airport. He was identified as Fayçal Cheffou by the Belgian media.

"The indications that led to the arrest of Fayçal C were not substantiated by the ongoing inquiry. As a result, the subject has been released by the examining magistrate," the Telegraph UK cited a statement of the Belgian federal prosecutor's office.

Cheffou, a Belgian national, was charged with "taking part in a terrorist group, terrorist murder and attempted terrorist murder."

The police had conducted raid at his house, but found nothing suspicious. However, the police knew him as a local activist who "rally asylum-seekers and homeless people to radical Islam," the Telegraph reported, adding that Cheffou was described as a freelance journalist.

Earlier Monday, the Belgium Police charged three more people, identified as Yassine A, Mohamed B and Aboubaker O, on charges of terrorist activities. They were detained during raids in Brussels and Mechelen, Duffel, Sunday. 

The Belgian prosecutors, however, did not reveal if they had any links with the March 22 attacks on the Zaventem airport and a metro at Maelbeek metro station, killing at least 35 people and injuring several others. The Islamic State group had claimed the responsibility for the attacks.