The second Brussels airport suicide bomber, Najim Laachraoui, was a suspected bomb maker for Islamic State's massacre in Paris and was already being hunted by police before the latest attack.
The 24-year- old was previously believed to be on the run after dumping a bag containing a bomb that failed to detonate and fleeing the airport on Tuesday.
But officials confirmed his DNA matched with that of one of two men who blew themselves up inside the terminal, as part of coordinated bombings that killed at least 31 people in the Belgian capital.
Laachraoui is believed to be pictured on the left, wearing a black top and a black glove on his left hand and pushing a baggage trolley, in a CCTV image taken at Brussels airport moments before the attacks, according to Belgian newspaper La Derniere Heure.
Authorities had already been searching for the Belgian national in connection with suspected Paris attacker Salah Abdeslam, who was arrested just four days before the Brussels bombings.
Earlier this week, Belgian prosecutors said that DNA evidence had identified Moroccan-born Laachraoui as being one of the accomplices of Abdeslam in the Paris attacks, which killed 130 people at sites including the Bataclan Theatre and Stade de France.
Laachraoui's DNA was said to have been found on "several explosive belts", as well as at hideouts in Auvelais and Schaerbeek which was used to prepare explosives and hide Abdeslam, French media reported.
He is suspected of making the explosive TATP, which can be made with household products and has been used by terrorists in improvised explosive devices and suicide vests, including in Paris.
He is also believed to have travelled to Hungary last year with Abdeslam and one other person in a Mercedes, which was checked by guards at the Austria-Hungary border and allowed to go on.
The federal prosecutor's office said on Monday they were seeking details about Laachraoui, who was undestood to have travelled to Syria in February 2013.
They believed he had used the pseudonym Soufiane Kayal to rent the safe house in Auvelais, a small town in the south of Belgium, and cross the Austria-Hungary border.
In an appeal for information in December, Belgian police said: "Salah Abdeslam has travelled twice during the month of September to the Hungarian capital Budapest using a rental car.
"On September 9 2015 he was subject to a check at the border between Hungary and Austria in a Mercedes.
"He was accompanied by two people using fake Belgian identity cards with the names Samir Bouzid and Soufiane Kayal.
"The same false identity of Soufiane Kayal was used to rent the house in Auvelais which was searched on November 26."
Laachraoui was a former pupil at the Institut de la Sainte-Famille d'Helmet Catholic school in the Schaerbeek area of Brussels and an electro-mechanics graduate, according to Belgian newspaper La Libre.