If you face drug possession charges in Illinois, this is a potentially serious crime for which you could face substantial jail time and fines if convicted. In order to convict you, however, the prosecutor must prove beyond a reasonable doubt that you actually possessed the drugs that law enforcement officers allege you possessed at the time they arrested you.
It may shock you to learn that, under some circumstances, the prosecutor can indeed convince a jury that you possessed the drugs in question even though officers did not find them in your pockets or anywhere else on your person.
Constructive possession is a legal doctrine stating that you possessed the drugs if you owned or controlled them. In other words, if the prosecutor can convince the jury that, based on the circumstantial evidence surrounding the drug bust, you controlled the location where officers discovered them, the jury can infer that you owned them and therefore convict you of possession.
To better understand constructive possession, consider the following example. The officer testifies at your trial that (s)he found the drugs in the locked console of your car which (s)he unlocked after obtaining its key as the result of a legal search of your car. Even though you had passengers in your car at the time officers found the drugs, the fact that you had the only key to the hiding place allows the jury to infer that you owned and therefore possessed the drugs. This assumes, naturally, that the jury finds the officer's testimony credible.
Now, change one detail of the above example. Again, the people involved are you, your passengers and the officer. Again, the officer testifies that (s)he found the drugs in your car's console while conducting a legal search of your car. This time, however, the console was unlocked. That one fact changes everything. Because your various passengers had the same access to your unlocked console as you did, any of them could have placed the drugs there just as easily as you could have. So, whose drugs were they? Based on this circumstantial evidence, the jury cannot infer the answer beyond a reasonable doubt.