The FBI has been placing small tracking devices on the cars of people of interest for years, apparently. Wired reports on the case of an environmental activist who noticed she was being followed and stopped by law enforcement for some time until the following just suddenly stopped. Soon after, she found a tracking device under the fender of her car. Wired worked with the people at iFixit who specialize in dismantling devices to see what's inside of them. The upshot: the tracking technology here is quite old, meaning that the same devices could have been in use for many years. The FBI's use of tracking devices is likely to come before the Supreme Court, which will decide on the constitutionality.