Belgium and the U.S. already said investigators were cooperating in the aftermath of the Brussels blasts, but now the creation of an "official" team was announced.
Van Leeuw was talking of "very concrete help". "This has already helped us a lot for a number of things. The Americans have a lot more potential - apart from international cooperation - compared to Belgium."
The magistrate was giving the example of deciphering locked messages and data. "I always received the same message about some encrypted messages: "This is not possible". But all of a sudden it was possible to read them. I won't go into further detail, but I think it's clear enough." Van Leeuw did not specify whether he was talking about cracking iPhones or reading WhatsApp messages.
Earlier, Belgium set up a joint investigation with France in the aftermath of the Paris attacks.