On Monday, a guy in California posted pictures of an FBI tracking device his friend found on his car to the social news site Reddit. Tuesday afternoon the FBI showed up at his friend's house and demanded it back.

Reddit user Khaledthegypsy posted this picture to Reddit, asking "Does this mean the FBI is after us?"

Don't Post Pictures of an FBI Tracking Device You Find on a Car to the InternetS

He wrote:

Me and my friend went to the mechanic today and we found this on his car. i am pretty confident it is a tracking device by the FBI but my friend's roommates think it is a bomb..any thoughts?

Turns out it was actually a tracking device. Wired's Kim Zetter reports that the owner of the car is a 20-year-old Arab-American named Yasir Afifi. Just 24 hours after his friend posted pictures of the device to Reddit, a couple of FBI agents showed up at Afifi's house, along with four police officers in SUVs and demanded the thing back.

From Wired:

Afifi retrieved the device from his apartment and handed it over, at which point the agents asked a series of questions – did he know anyone who traveled to Yemen or was affiliated with overseas training? One of the agents produced a printout of a blog post that Afifi's friend Khaled allegedly wrote a couple of months ago. It had "something to do with a mall or a bomb," Afifi said.

The whole story is worth reading, and the level of detail the agents knew about Afifi's life it details is chilling. (Afifi's deceased father was a prominent member of the local Muslim community and was on a federal watchlist.) The FBI left Afifi with "You don't need to call your lawyer. Don't worry, you're boring," according to Wired.

It's amusing how the tables were turned on the FBI on this one as the surveiller became the surveilled. But next time, don't help the creeps out by posting evidence of their shoddy work to the Internet.