West's Key Number Digest, § 89. Investigatory stop or detention
Although a mere hunch does not create reasonable suspicion for an investigative stop, the level of suspicion that the reasonable suspicion standard requires is considerably less than proof of wrongdoing by a preponderance of the evidence, and obviously less than is necessary for probable cause. U.S.C.A. Const.Amend. 4. Navarette v. California, 134 S. Ct. 1683 (2014).
Although reasonable articulable suspicion is considerably less than proof of wrongdoing by a preponderance of the evidence and is less demanding even than the "fair probability" standard for probable cause, it nevertheless demands the articulation of reasons to believe the person to be stopped is committing, has committed, or is about to commit a crime, beyond an inchoate and unparticularized hunch; similarly, although reasonable suspicion is a less demanding standard in the sense that it can arise from information that is less reliable than that required to show probable cause, reliability is nevertheless also a consideration in the evaluation of reasonable suspicion. U.S. Const. Amend. 4; Colo. Const. art. 2, § 7 People v. Mason, 2013 CO 32, 310 P.3d 1003 (Colo. 2013).
West's Key Number Digest, § 14. Showing of probable cause
In determining whether probable cause exists to issue an arrest warrant, a magistrate is not required to find a showing of criminal activity, as the mere probability of such criminal activity is sufficient for probable cause, and furthermore, the information offered to demonstrate probable cause must be viewed in a common sense, nontechnical, ungrudging and positive manner. A court must limit its inquiry to the information within the four corners of the affidavit submitted in support of probable cause when determining whether the arrest warrant was issued upon probable cause. Thus, the determination of probable cause for an arrest warrant is made from the facts as known at the moment the warrant is requested and is unaffected by facts later discovered. 5 Am. Jur. 2d Arrest § 14