Two brothers—Khalid and Brahim El Bakraoui—have been identified by Belgian media as suspected suicide bombers in the attacks on Brussels yesterday that left 34 people dead and more than 200 injured. The brothers both spent time in prison for non-terrorism-related crimes, and have been wanted by Belgian police since March 15. A suspected third perpetrator remains at large. The Washington Post reports that another person with ties to the plot has been arrested, though it’s not clear whether he’s the third attacker. The Post reports that he may be Najim Laachraoui, a suspected bomb maker who traveled to Syria in 2013 and is also wanted in connection with the Paris attacks in November 2015. It remains unclear whether the Brussels attacks were related to the capture in Belgium last week of Salah Abdeslam, the only survivor of the group of terrorists who attacked Paris. Brussels remains on virtual lockdown, as the country comes to grips with a problem that runs deeper than previously thought—“a sympathetic milieu for terrorist cells to form, hide, and operate in the center of Europe,” as The New York Times writes.