"Illegal possession" refers to the act of having or owning something that is prohibited by law. It means keeping or holding onto an item or substance that you are not allowed to have. Full definition
Where the act of theft and the possession of stolen goods are done at the same time, the person can not be convicted of illegal possession of the same things they stole. (slsedmonton.com)
In actuality, however, one can be charged for illegal possession of prescription drugs. (drugtraffickingatty.com)
He is currently in police custody with 4 others who have also been charged with illegal possession of arms. (citifmonline.com)