Legal Question in Traffic Law in Illinois

As long as the officer has probable cause to arrest someone it is considered legal. Probable cause is legal term and requirement which allows a person to be arrested and taken into custody for further processing. In this case he saw the person driving and further investigated and found out and/or confirmed that they were driving on a suspended license which means that they were breaking the law. So there appears to have been probable cause to arrest the person. My question is - did he get a warrant? If not, there may be grounds to argue it was improper. A good criminal attorney should be contacted to advise this person further, especially if there is an upcoming court case. Good luck.