The suicide bombers who carried out a deadly attack on Brussels airport were brothers and known to police, according to reports.
Both brothers had criminal records but had not previously been linked by police to terrorism until now, Belgian media reported.
Khalid had rented under a false identity the house in Brussels raided by police last week, in an operation that later led to the arrest of Paris attacks suspect Salah Abdeslam.
It has emerged Brahim, 30, had been sentenced to nine years in prison after being convicted in October 2010 of firing a Kalashnikov assault rifle at police and wounding an officer after a robbery in Brussels earlier that year.
In 2011, his brother Khalid was given a five year jail sentence for car jacking.
The details of the attackers came amid reports their alleged accomplice, who went on the run apparently after his device failed to explode, had been captured.
Najim Laachraoui, who was arrested in Brussels' Anderlecht district, had been identified by French police as the chief bombmaker for the Paris attacks last November.
CCTV footage taken in the moments before the twin blasts at Zaventem Airport, which left at least 14 people dead, showed two of the three men wearing single gloves to conceal detonators.
:: Brussels Attacks: What We Know So Far
The explosives were contained in their luggage and detonated before reaching the security gate, according to Zaventem's mayor.
Investigators were tipped off by police by a taxi driver who had driven three "suspicious" individuals to the airport - and was told not to touch their luggage upon arrival.
He directed police to the house where he had picked them up in the Brussels suburb of Schaerbeek.
Inside the property detectives found a nail bomb, chemical products and an Islamic State flag.
Belgium is continuing to mourn following the airport attack and the subsequent explosion on a tube train at Maelbeek Metro station, which killed a further 20 people.
One of the 34 people confirmed to have died in the bombings on Tuesday was 37-year-old Adelma Tapia Ruiz, the mother of three-year-old twins. She was killed while checking in at the airport.
Among the missing is Brussels commuter David Dixon, originally from Hartlepool, who failed to arrive at work on Tuesday morning.
Islamic State has claimed responsibility for both atrocities, and in a statement, the terror group warned of "dark days" ahead for the western nations against it.
:: In the UK, anyone affected or concerned about others caught up in the attacks can call +442070080000.
:: The Belgian Crisis Centre has also set up a helpline for people calling from outside Belgium: +3278151771. Those in Belgium are asked to call 1771.