The trial court properly denied defendant's motion to suppress evidence of the gun found concealed on his person, where based upon the totality of the circumstances: 1) the officers' actions to determine whether defendant was armed were reasonably necessary for their protection and did not result in his de facto arrest; 2) the officers had sufficient articulable facts to support their reasonable suspicion that defendant had committed a felony, namely, possession of a firearm in a school zone; and thus, 3) the investigative stop was constitutionally permissible.