From yesterday's Washington Court of Appeals decision in State v. Tarango:

At around 2:00 in the afternoon on a winter day in 2016, Carlos Matthews drove to a neighborhood grocery store in Spokane, parking his car next to a Chevrolet Suburban in which music was playing loudly. A man was sitting in the passenger seat of the Suburban, next to its female driver. When Mr. Matthews stepped out of his car and got a better look at the passenger, who turned out to be Ismael Tarango, he noticed that Mr. Tarango was holding a gun in his right hand, resting it on his thigh. Mr. Matthews would later describe it as a semiautomatic, Glock-style gun. As he headed into the store, Mr. Matthews called 911 to report what he had seen, providing the 911 operator with his name and telephone number….

The police came out, stopped the car (which had left the parking lot), and found a gun, which the prosecutor argued was possessed by Ismael Tarango, who had prior felony convictions. Tarango was prosecuted for illegally possessing the gun, but the court concluded that the search was unconstitutional:

Because the officers conducting the Terry stop [i.e., a brief investigative stop] of the Suburban had no information at the inception of the stop that Mr. Tarango or Ms. Hutchinson had engaged in or were about to engage in criminal activity, they lacked reasonable suspicion. The motion to suppress should have been granted.

For a Sixth Circuit case involving a similar claim, see this post from 2014.