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.

Thirty eight people were killed and dozens survived a plane crash in Kazakhstan while traveling to southern Russia, according to local officials, as speculation swirls online that Russia could somehow have been responsible for the crash.

A day after an Azerbaijani airliner's crashed in Kazakhstan, aviation experts say the plane most likely went down after being hit by Russian air defense systems. Here are some things to know about