The Embraer 190 was traveling to Grozny, Russia, but crashed near Aktau, Kazakhstan, killing 38 people onboard. Investigators are focusing on Russian air defense as the likely cause.

Russian aviation authorities did not allow the plane to land in any of the multiple airports nearby, forcing the pilots to fly over the stormy Caspian Sea to try to land in the western Kazakh city of Aktau. The plane crashed close to Aktau airport.

The second black box has been found at the plane crash site near Aktau and handed over to the investigation department, according to a Kazakh official from transport department on Thursday. The Embraer 190 aircraft operated by Azerbaijan Airlines flight J2-8243 from Baku to Grozny crashed near Aktau Airport in Kazakhstan on Wednesday.