Prisoners at a San Diego jail are facing a major crackdown after they managed to take part in the viral Internet “Mannequin Challenge” phenomenon, despite a ban on mobile phones in prison.

Participants in the video trend pose mid-action - like mannequins - while someone roams the scene and records it on their camera. The result is similar to the “Bullet Time” effect in the Matrix movies.

But prison officials are baffled as to how prisoners took part.

The video shows a mock fight, a number of prisoners with mobile phones and a group of prisoners huddled over contraband.

The California Department of Corrections and Rehabilitation confirmed to NBC News that the footage was shot inside the Richard J. Donovan Correctional Facility in Otay Mesa, California.