If you still come up in their searches as being under a federal investigation which lasts 3 yearson your record regardless, then they can search you without suspicion, the open federal matter is enough.
Then if they find anything in the car, clean unopnened fits, baggies whatever, they can drag you back to the local police station and strip search, you know the whole raise your nutsack, squat and cough.
I've done a lot of googling but I can't find anything saying that a person can be searched if you've had an investigation on your record.
from http://www.findlaw.com.au/articles/4338/can-the-police-conduct-a-personal-search-without-a.aspx
When can the police conduct a search without a warrant?
The police can search a person without obtaining a warrant if they have reasonable grounds to believe that the person has in their possession:
• a dangerous weapon
• illicit drugs
• stolen, or unlawfully obtained property
• an object to commit a crime, or cause harm to themselves, or to another person.
Can I not consent to a search?
A person does have the right to refuse a request for a bodily search. However, consent does not need to be obtained if the police have reasonable grounds to believe that a person has in their possession weapons, drugs, or stolen property.
If a police officer is seeking a person’s consent to conduct a search, the consent must be genuinely obtained. An officer conducting a search must clearly state that a search is to be conducted, and that the person not only understands the request being made, but gives permission for a search to take place.

