Belgian officials, providing the first details of the twin terror attacks in Brussels that killed at least 31 people, said two brothers originally thought to be at the airport together were actually at two different locations and that one huge bomb left by a third terrorist failed to detonate at the airport.

In addition, police, tipped by a taxi driver, have raided a bomb making house in the Brussels neighborhood of Schaerbeek and confiscated explosives and a computer, found in a street trash can, that contained a suicide note from one of the attackers.

The terrorist, identified as Ibrahim El Bakraoui, 29, said in the note that he felt increasingly unsafe and "did not want to end up in jail."

Federal prosecutor Frederic Van Leeuw said at least one of three men captured in surveillance video at the airport had been identified El Bakraoui. One of the other men, seen wearing a hat, and believed to be Najim Laachraoui, was pushing a cart with a 35-pound bomb that failed to go off. He was seen leaving the airport and is being sought.

The third person at the airport was initially identified as Ibrahim's 27-year-old brother, Khalid, but police now say that Khalid was the suicide bomber who set off an explosive device at a Brussels metro station.

The prosecutor did not discuss the reported arrest of a suspect in the case. Initially, state TV and some Belgian media reported that Laachraoui, who is also linked to the Nov. 13 Paris bombing that killed 130 people, was picked up. But the report was later retracted.

Laachraoui is believed to be the only surviving prime suspect in the bombings, according to CNBC. His DNA was also found on explosive material in the November attacks in Paris. The Belgian newspaper La Libre initially reported that Laachraoui was in custody, but later said the man arrested in Anderlecht, Belgium had been misidentified.

The El-Bakraoui brothers were known to the police, RTBF said. Their involvement has not been publicly confirmed by investigators. The Islamic State claimed responsibility for the attacks.

Police got a big break on Tuesday when a taxi driver came forth to say that he had picked up the three men seen in the airport video. They immediately raided the house in Schaerbeek based on the driver's information. The prosecutor said police confiscated more than 30 pounds of explosives, trigger devices and nails used in bombs as shrapnel. In addition, police digging in a trash can on the street found a computer that contained Ibrahim El Bakraoui's suicide note in French.

His expression of concern that he might end up in jail likely was triggered by the arrest last week of Salah Abdeslam, who police said has confessed to his role in the Paris attacks. Abdeslam's lawyer said his client was cooperating with police, which could have provoked El Bakraoui's to think that police might be closing in on his terrorist network.

French Prime Minister Manuel Valls, who is visiting Brussels Wednesday, called on the EU parliament to authorize a passenger name record for the continent, according to the Associated Press. The proposal authorizes the blanket collection of passenger data and has been under consideration by parliament on and off again since 2011.

“It is urgent to adopt the European PNR," Valls said. The European Parliament has waited too long to adopt this text. It must examine and adopt it in April, it’s time.”

Brussels Airport remained closed Wednesday because the forensic investigation is still taking place. A minute’s silence was scheduled for midday local time to commemorate the victims.

The metro station bomb was denoted near offices belonging to the European Union. The Belgian prosecutor’s office said police found a fourth explosive device, which was not detonated, containing nails, chemical products and an Islamic State flag in a house in the Schaerbeek neighborhood of the city Tuesday.

The attack came four days after the arrest of Salah Abdeslam, a suspect in November's Paris attacks who was captured in Brussels after a four-month manhunt.

Belgian authorities said Abdeslam had planned to commit another attack and had a large network of associates. Officials on Tuesday said it was too soon in the investigation to tie Tuesday's attacks to the Paris assaults that killed 130 people.

RTBF said Khalid Bakraoui had rented an apartment which was raided by police last week in an operation. That investigation led authorities to top Paris attacks suspect Salah Abdeslam.