When someone is convicted for possession of drugs or drug paraphernalia, the state has to prove that there was "actual or constructive" possession of a controlled substance and or paraphernalia.
Actual possession is when the item is in the hands of or on the person in question. It can also be in extremely close proximity of the suspect. When it comes to constructive possession, the drugs are not found on the person. The prosecution must prove beyond a reasonable doubt that the defendant knew of the presence of the drugs and that they had the ability to control it.
Sounds difficult for the state to prove this, right? It can be. A good defense lawyer can poke holes in the state's case when they can't prove the defandant had dominion over the drugs, or that the defendant even knew about the drugs or the illicit nature of such contraband. This can all apply to being arrested on any drug charge, such as distribution, trafficking or possession. If you are ever in such a legal jam, it's important to know that just because you are in a room that happens to have drugs in them doesn't mean you are going to jail. Being near drugs, without your knowledge, is usually not enough for the state to convict someone. So whether the police find drugs on you or in your hands (actual possession), or if the police stops your car or serves you a warrant at home where there might be some access to drugs (constructive possession), you and your defense have many available legal options to prove your innocence.