After an Azerbaijan Airlines jet crashed in Kazakhstan, speculation mounted about why the plane went down and whether possible Russian air defense action may have played a role.

U.S. officials say Russia could be behind a passenger plane crash in Kazakhstan that left dozens dead on Christmas Day. U.S. officials say it looks like the plane was hit by a Russian air defense system,

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.