The Alabama Department of Corrections is investigating how it was possible to film the clip.

A video has surfaced online from within a prison in Alabama showing at least 30 inmates doing the Mannequin Challenge.

Powerful storms stretching from the US Gulf Coast to the Great Lakes in the north wrecked two small towns and killed at least 28 people as the system tore roofs off schools and homes and damaged a maximum-security prison. It was the second deadly tornado outbreak this week.