Like other law enforcement agencies, the FBI needs probable cause to carry out a full-scale investigation. Agents can't just come to your home, go inside and start looking around to see what evidence they can find.
However, the FBI can carry out an "assessment" without official probable cause or solid evidence. If they have a hunch that you may have broken the law, they can take steps to begin investigating, even if you've done nothing. A few things they are legally allowed to do during the assessment include the following:
-- They can come to your house and look in your garbage bins. They'll often do this as a way to find evidence that could then lead to a warrant and a more complete search of the inside of the house.
-- They can ask you to take a lie detector test. Lying while taking the test could be probable cause for a warrant to look into whatever it is you were lying about.
-- They can use a surveillance squad to keep an eye on your activities. This could mean camping out in front of your home or it could mean following you around. The squad can't come into your house, but it's easy enough to follow you in public areas -- like when you're driving to work, for example, or going out to dinner with your family.
If you are facing federal charges and you think law enforcement may have taken things too far, it could be that evidence was gathered illegally. This is why it's important to know what they can and cannot do, along with your legal options in Florida when lines are crossed.
Source: Gizmodo, "The FBI Just Gave Itself Permission to Follow You and Go through Your Trash," Sam Biddle, accessed May 26, 2016