As the number of victims in the Brussels suicide attacks rose to 35, Belgian police released a video of a mysterious "man in white" seen in the company of the bombers who attacked Brussels Airport, indicating that he is still at large.
"Police are seeking to identify this man," the Belgian Federal Police's website said.
In the police raids that followed the March 22 attacks, Belgian authorities said a man identified as Faycal Cheffou was among those taken into custody and facing preliminary terror charges.
Belgian media had claimed the man was the mysterious suspect in the white jacket and dark hat spotted with the two bombers at the airport the morning of the attacks.
But on Monday, a Belgian magistrate ruled that new evidence uncovered by investigators revealed there were no grounds to keep Mr Cheffou in custody and he was released, the Belgian Federal Prosecutor's Office said.
Eric Van der Sijpt, a spokesman for the prosecutor's office, added to confusion when he said the charges against him remained for the moment.
"We're not saying that he's innocent. That we do not do," Mr. Van der Sijpt told the New York Times. "It's that he's no longer needed in prison. But there are two different things. Preventative custody has nothing to do with the actual investigations or the charges brought."
Only at the end of the investigation would the prosecutor decide whether or not to prosecute Mr Cheffou.
The Belgian Federal Police's website posted a 32-second video of the still-unidentified suspect as he wheels baggage through the terminal alongside the bombers.
"If you recognise this individual or you have information concerning this attack, please contact investigators," police asked.
Belgian authorities also announced that three more people swept up in police raids that followed the attacks on the airport and on a Brussels subway train were being held on charges of participating in terrorist activities.
It was not clear if the suspects ordered held by an investigating judge were linked to the attacks themselves. The three - identified by Belgian prosecutors as Yassine A., Mohamed B. and Aboubaker O. - were detained during 13 police searches Sunday in Brussels and the northern cities of Mechelen and Duffel.
The federal prosecutors' office provided no details of the alleged actions committed by the suspects and released a fourth person without charge.
The bombings, the bloodiest in recent Belgian history, were claimed by the Islamic State extremist group and confirmed Belgium's status as an unwitting rear base from which Muslim extremists can stage attacks in Europe. Many of those responsible for the Nov. 13 attacks in Paris that killed 130 people and wounded hundreds came from Belgium.
Four more people wounded in the Brussels attacks died in the hospital, Belgian Health Minister Maggie De Block announced on her Twitter account Monday.
She posted: "Four patients deceased in hospital. Medical teams did all possible. Total victims: 35. Courage to all the families."
Four patients deceased in hospital. Medical teams did all possible. Total victims: 35. Courage to all the families. #BrusselsAttacks— Communicatie (@Maggie_DeBlock) March 28, 2016
De Block had reported over the weekend that 101 of the 270 wounded in the blasts were still being treated in hospitals, including 32 in burn units. A doctor at one of those burn units who had once served in Afghanistan described patients' wounds as shocking.
One week after the devastating attacks, which severely damaged Brussels Airport's departure area, the facility is planning to test its capacity to partially resume passenger service.
Florence Muls, an airport communications manager, said 800 staff members on Tuesday will test temporary infrastructure and new arrangements designed to handle passenger check-ins.
It's too early to say when airport service might actually resume, she said, adding that government and firefighters must approve the new system before Brussels Airport can start handling passenger traffic again.
Before the bombings, Brussels Airport served some 600 flights a day and 23.5 million passengers per year.
