The cause of the crash of Azerbaijan Airlines flight J2-8243 near the city of Aktau, Kazakhstan, is still unknown. The Kremlin has so far been tight-lipped, prompting questions over its messaging.

The plane, which crashed in Kazakhstan this week, went down “due to external physical and technical interference,” according to the investigation’s preliminary findings.

Experts say evidence in the Azerbaijan Airlines plane crash in Kazakhstan points to a possible midair explosion, not an encounter with a flock of birds.