"FBI hostage negotiators used surveillance drones during a standoff earlier this year with an Alabama man who had taken a boy hostage inside a makeshift underground bunker.
"Asked by Sen. Dianne Feinstein (D., Calif.) about what privacy protections are used in deploying drones and storing the images they collect, Mr. Mueller said their use was narrowly focused on specific incidents.
" 'It's very seldom used and generally used in a particular incident when you need the capability,' said Mr. Mueller, who said he wasn't sure what becomes of the images recorded by such drones. 'It is very narrowly focused on particularized cases and particularized needs.' "