Najim Laachraoui, left, Brahim el-Bakraoui, center, and an unidentified suspect. | CCTV via Belgian police Belgium arrests man, denies it’s Najim Laachraoui Najim Laachraoui was already wanted in connection with November’s Paris attacks.

Belgian police arrested someone suspected of involvement with Tuesday's bomb attacks in Brussels, the Belgian prosecutor said Wednesday.

Federal prosecutor Frédéric Van Leeuw said Belgian-born Brahim el-Bakraoui carried out the airport attack, which killed at least 11 people, together with a second suicide bomber who has not yet been publicly identified. His brother Khalid el-Bakraoui detonated a bomb on a subway train at Maalbeek station in the heart of the city’s EU district, killing at least 20 people. The el-Bakraoui brothers had police records, the prosecutor said, but did not previously have known links to terrorism.

A third suspect, captured on CCTV shortly before the blasts, fled the scene without detonating his bag of explosives and was still at large, Van Leeuw said.

“The person with the clear-colored vest has disappeared. His bag had contained the most important explosive device. The person has not been identified and is still being looked for,” the prosecutor said.

Security officials denied reports that Najim Laachraoui — who has also been linked to the preparations for the Paris attacks last November — was detained in Anderlecht.

The Washington Post later reported that Laachraoui was the second suicide bomber at Zaventem airport, citing an Arab intelligence official and a European intelligence official, both unnamed. Belgian media also reported that Laachraoui had blown himself up citing anonymous sources.

Laachraoui was already wanted by police after he was linked to the Paris attacks in November.

This article has been updated to reflect conflicting reports about the status of Najim Laachraoui.