How the Brussels Attacks Unfolded

PHOTO: Travelers stand in a smoke filled terminal at Brussels Airport, in Brussels after explosions, March 22, 2016.PlayRalph Usbeck via AP Photo
WATCH Brussels Attack: What We Know About Suspected Terrorists

A day after the deadly bombings in Brussels that left at least 31 dead and at least 270 injured, including 61 in intensive care, new details are beginning to emerge about the day of the attacks and the ensuing manhunt.

Investigators are still searching for one suspect and are working to identify a second dead bomber, having only been able to identify two of the four alleged attackers so far.

Now other governments are coming out with new information about the suspects as well, suggesting that the Belgian government was previously warned about the potential threat one of the suspects posed.

Here is the way officials have said the day unfolded:

A taxi driver, who later spoke to police, picked up three men at an address about five miles away from the international airport in Brussels.

Each man had a large suitcase, and they were later pictured on airport surveillance footage carrying a bag each on luggage carts.

PHOTO: An image made from a security camera and released on March 22, 2016 by the Belgian federal police shows what the police say are possible suspects in the Brussels airport attack.Belgian Federal Police/AFP/Getty Images
An image made from a security camera and released on March 22, 2016 by the Belgian federal police shows what the police say are possible suspects in the Brussels airport attack.

7:58 a.m.: First Explosions at the Airport

One blast went off at 7:58 a.m. near Lane 11 in the departure hall and the second went off nine seconds later near Lane 2.

A third device was found inside a suitcase, but it had not detonated. The bomb later went off on its own while the bomb squad was on site because it was so unstable.

The number of people who died at the airport has fluctuated, but at least 10 people are believed to have died at the airport, not including the suspects.

9:11 a.m.: Second Attack in the Center of the City

A fourth bomb was used in a different location about an hour after the airport attack occurred.

An explosion went off in the second car of a train as it was pulling out of the Maelbeek station, which is located near some European Union offices.

PHOTO: Fallen bricks from a wall in a car park are seen following an explosion at Maelbeek metro station following an attack on March 22, 2016 in Brussels. Alexander Koerner/Getty Images
Fallen bricks from a wall in a car park are seen following an explosion at Maelbeek metro station following an attack on March 22, 2016 in Brussels.

Officials later said that the bomber in this attack was Khalid El-Bakraoui, the 27-year-old brother of one of the suspected suicide bombers from the airport attack.

The death toll continues to change, but it was initially reported that there were at least 20 people killed at the train station.

The Investigation Begins

The taxi driver who drove the airport came forward to police and gave them information about the pickup site.

"An investigation has been launched at this address and that’s where we found 15 kilos of explosives of TATP, 150 liters of acetone, 30 liters of oxygenized water, detonators, a suitcase filled with nails and screws as well as other materials to build explosives," Belgian prosecutors said Wednesday morning.

There were two other investigations launched on that same street but they yielded no tangible evidence, the official said.

One piece of information that was found outside the apartment building was a laptop that had been put in a trash can on that same block. Investigators were able to determine that the computer belonged to Ibrahim El-Bakraoui, one of the airport suicide bombers.

"The note included mentions of 'being in a rush,' 'no longer knowing what to do,' 'being sought everywhere,' 'no longer being safe,' and that if he takes too much time, he risks finishing his life 'next to him' in a jail cell," an official said. It was unclear who "him" refers to.

Around 4 p.m. local time: ISIS Claims Responsibility

An ISIS-affiliated website reported that the terror group claimed responsibility for the attacks, claiming its "fighters" carried out the bombings against "the Belgian capital of Brussels, a country participating in the international coalition against the Islamic State."

PHOTO: A Belgian police officer is seen searching an apartment in Schaerbeek, after an explosion at Maelbeek Metro station, Brussels, March 22, 2016.Laurent Dubrule/EPA
A Belgian police officer is seen searching an apartment in Schaerbeek, after an explosion at Maelbeek Metro station, Brussels, March 22, 2016.

Unanswered Questions

Investigators are still working to piece the narrative together, trying to identify any individuals who may have helped the bombers, as well as trying to confirm the identities of the two remaining bombers.

There were two further searches launched Tuesday after the apartment building, and both resulted in individuals being arrested.

The first person, who has not been named, was arrested after a search in the neighborhood of Schaerbeek and he remains in custody. That person was not one of the suspected bombers and it was not clear what the circumstances of the arrest were.

The second came after another search but that individual has since been released, officials said.