The Fourth Amendment of the United States Constitution and Article I, 5, of the Louisiana Constitution protect people against unreasonable searches and seizures. The right of law enforcement officers to stop and interrogate one reasonably suspected of criminal conduct, however, is recognized by La. C.Cr.P. art. 215.1, as well as both federal and state jurisprudence. Terry v. Ohio, 392 U.S. 1, 88 S. Ct. 1868, 20 L. Ed. 2d 889 (1968); State v. Stewart, 97-2399 (La. App. 1st Cir. 9/25/98), 721 So. 2d 925. Reasonable suspicion for an investigatory detention is something less than probable cause and must be determined under the facts of each case by whether or not the officer had sufficient knowledge of facts and circumstances to justify an infringement on the individual's right to be free from governmental interference. The right to make an investigatory stop and question the particular individual detained must be based on reasonable cause to believe that he has been, is, or is about to be engaged in criminal conduct. State v. Tucker, (La. App. 2d Cir. 1992), 604 So. 2d 600, affirmed in part, reversed in part, 626 So. 2d 707 (La. 1993); State v. Stewart, supra; State v. Colarte, 96-0670 (La. App. 1st Cir. 12/20/96), 688 So. 2d 587, writ denied, 97-1015 (La. 10/3/97), 701 So. 2d 197. Under such circumstances, a law enforcement officer may stop a person and may demand of him his name, address and an explanation of his actions. State v. McHugh, 92-1852 (La. 1/6/94), 630 So. 2d 1259. the necessary reasonable suspicion has been defined as "articulable knowledge of particular facts which, in conjunction with reasonable inferences drawn therefrom, is sufficient to provide reasonable grounds to suspect criminal activity." State v. McBarry, 97-0025 (La. App. 4th Cir. 8/20/97), 699 So. 2d 127. The officer must have sufficient facts within his knowledge to justify an infringement of the suspect's rights. An inchoate or unparticularized hunch or mere suspicion is insufficient to establish reasonable grounds to stop a person. State v. Tucker, supra; State v. Leary, 627 So. 2d 777 (La. App. 2d Cir. 1993), writ denied, 93-3187 (La. 3/25/94), 635 So. 2d 237. La. C.Cr.P. art. 215.1 provides in pertinent part: A. a law enforcement officer may stop a person in a public place whom he reasonably suspects is committing, has committed, or is about to commit an offense and may demand of him his name, address, and an explanation of his actions. B. When a law enforcement officer has stopped a person for questioning pursuant to this Article and reasonably suspects that he is in danger, he may frisk the outer clothing of such person for a dangerous weapon. If the law enforcement officer reasonably suspects the person possesses a dangerous weapon, he may search the person.C. If the law enforcement officer finds a dangerous weapon, he may take and keep it until the completion of the questioning, at which time he shall either return it, if lawfully possessed, or arrest such person. In order to assess the reasonableness of an officer's conduct, it is necessary to balance the need to search or to seize against the harm of invasion. State v. Stewart, supra. Whether an officer has a reasonable suspicion to make an investigatory stop should be determined under a totality of the circumstances, in light of the officer's experience, training and common sense. The officer's experience may be a consideration in ascertaining whether his inferences from the given facts were reasonable. State v. White, 27,188 (La. App. 2d Cir. 8/23/95), 660 So. 2d 515, writ denied, 95-3045 (La. 4/25/97), 692 So. 2d 1076. Flight, a furtive gesture, nervousness, or startled behavior at the sight of a police officer is not, by itself, sufficient to justify an investigatory stop. This type of conduct, however, may be a factor leading to a finding of reasonable suspicion. Presence in a high crime area, coupled with nervousness or flight or suspicious actions on approach of officers is sufficient to justify an investigatory stop. Such a high crime area is a place in which the character of the area gives color to conduct which might not otherwise raise the suspicion of the officer. State v. White, supra. To assess the validity of an investigatory stop under Terry v. Ohio, supra, and its Louisiana statutory equivalent, La. C.Cr.P. art. 215.1, the critical inquiry must focus on the knowledge in the officer's possession at the time of the stop and whether that knowledge constitutes reasonable cause for a stop. State v. Dorsey, 27,509 (La. App. 2d Cir. 11/1/95), 662 So. 2d 857.