Belgium’s top prosecutor says at least one of the suspects involved in the Brussels bombing is still on the loose as authorities work to identify all the men involved in the plot that left at least 34 dead and hundreds more injured Tuesday.

Belgian prosecutor Frederic Van Leeuw said at a press conference Wednesday that authorities have only identified one of the men in a surveillance photo from the airport—Ibrahim El Bakraoui, a 29-year-old suicide bomber standing in the middle of the picture, who was apparently identified based off a fingerprint.

He apparently left behind a will on a computer that had been thrown in a trash can in the Brussels neighborhood of Schaerbeek, which said in part that he felt “increasingly unsafe and feared landing in prison.”

Authorities say El Bakraoui’s brother, 27-year-old Khalid El Bakraoui, was also involved in the plot and died blowing himself up in the Maelbeek subway station bombing.

The brothers had a criminal history and were “known to police,” but their crimes were not related to terrorism—Ibrahim was reportedly convicted of shooting at police officers during a botched robbery and Khalid was convicted on charges of attempted carjacking.

Still, according to the New York Times, several Belgian news reports indicate they were linked to a March 15 terrorism raid and were wanted by police when the attack occurred.

Both El Bakraoui and the man standing to his right in the surveillance photo died Wednesday when they blew themselves up at the airport, nine seconds apart.

Van Leeuw says police are currently searching for the man in the white coat standing on the right, who fled after leaving behind a suitcase bomb that failed to detonate. Via the AP:

That suspect took flight and left behind a big bag at the airport before the two explosions. Van Leeuw says that bag turned out to have the heaviest load of explosives of all and blew up later when the bomb squad was there due to the instability of the explosives. Van Leeuw says fortunately no one was injured.

A cab driver who took the three men to the airport also led police to a home in Brussels where a bomb squad discovered about 33 pounds of TATP explosives—the same type used in the Paris attacks.

At least two other people have been arrested in connection with the attack—one who was taken into custody on a train headed for Amsterdam Tuesday and another in a raid on an apartment building in the Brussels neighborhood of Anderlecht on Wednesday.