While driving a friend's car, police found drugs in the vehicle and arrested me. Why was I charged with drug possession?
Keep in mind that for someone to be arrested for drug possession or any other offense, most states only require that an officer have probable cause to make the arrest.
Probable cause is a much lower standard of proof than what is required for a conviction. Depending on the laws of your state, the officer most likely had probable cause to arrest you, but whether or not it will be enough to convict you depends on the standards for establishing guilt in your jurisdiction.
"Wing-Span" and "Control of Vehicle"
Probable cause is subject to interpretation by jurisdiction. Even within a state, different appellate courts often disagree on what truly creates probable cause. You were most likely arrested and charged because the state where you were arrested uses a "wing-span" or "control of vehicle" approach. Wing-span simply refers to how far you can reach. If you're driving a small car and can easily reach almost any location in the car where the drugs are found, that would be enough to satisfy probable cause. The theory is that if you could "reach" the drugs, then you legally possess the drugs.
The "control of vehicle" approach is also what its name implies: if you were in control of the vehicle, then you were also legally in control of its contents, including any drugs found. Some states require more than an assumption. For example, in Virginia, the law specifically does not allow for the presumption that drugs found in a car belong to the driver/occupant or owner of the car. It is only "some evidence" of possession.
A Criminal Defense Attorney Can Help You Fight the Charges
Even if you live in a wing-span or control of vehicle jurisdiction, you will not necessarily be convicted of drug possession based on these assumptions. Every jurisdiction allows you to rebut assumptions like these with your own evidence and testimony. The fact that other individuals also operated the car on a regular basis lends credence to your defense. The struggle that you will have is getting someone else to own up that they were also driving a car that contained drugs. You may have to rely on eyewitnesses who saw them driving, and submit vehicle registration records to show that someone else owned the car.
You can also request that the items found be independently tested for prints – thereby proving that you never actually touched the drugs. If you are charged with drugs found under a seat in a car, you should consult with a criminal defense attorney as soon as possible so that they can assist you in invoking your rights before any evidence valuable to your case is mishandled or lost.