This week a former assistant director of the FBI's Operational Technology Division has spoken up on a single case which has subsequently revealed a lot of pointed spying abilities of the institution itself. Speaking up on terror suspect "Mo", Marcus Thomas has let it be known that they've been able to break into (some) computers for years, able to turn on their webcams remotely, and that they're able to do this without triggering the webcam's red light. In other words, they're able to see through a computer's webcam without the computer's owner knowing.
Inside this FBI investigation of the suspect named "Mo," Thomas let the Washington Post know that they used a number of abilities only for the "most serious" criminal investigations. He made clear that the technology was "mainly" used for terrorists, but made no solid indication that its use was limited to this one suspect.
With a target like Mo, the FBI sought to use any means necessary to track his threats of university school bombings and airport attacks in the USA inside 2012. At the moment it would appear that Mo is well outside the United States, believe to be sitting somewhere inside Iran, and the FBI is currently holding quite a stack of information on him. They also used means such as Yahoo Mail delivery to track the websites he'd frequented (scary stuff, no matter who he really is) using malware he (apparently) had no idea he'd installed.
While it would seem that activating cameras remotely "without triggering the light that lets users know it is recording" has been an ability of the FBI's for years, it's unlikely they're spying on you specifically. Don't forget what happened to Eric Cartman (warning: foul language), after all.
Have a peek at the timeline below for additional bits and pieces that've been spilled on the FBI and/or the NSA over the past few weeks. This isn't all one organization, but to those that would have an aneurysm over their abilities to spy on anyone and everyone, they may as well be.