Officers muted body cameras in Stephon Clark shooting. Why?

CNN, 26 MARCH 2018, FEAT. PROF. SETH STOUGHTON:

About seven minutes after Sacramento police fatally shot an unarmed black man in his grandmother’s backyard last week, officers were instructed to mute their body cameras.

Stephon Clark, 22, was in the backyard March 18 when two police officers shot at him 20 times. Police said they thought he was holding a gun. But investigators say they did not find a weapon at the scene, only a cellphone near the man’s body.